Following a small conversation with our good Doktober, I saw this as a good place to ramble on about some unit ideas that crossed my mind- the intent is to suggest more to the roster without drastically increasing the required workload on things like brand new models or custom animation sets.
Largely, these units will be on the upper echelons of quality and thus be more elite than the current roster, largely because the current additions are sufficient in the middle and lower echelons in my mind.

Thus, without further ado, I present in no particular order, a series of units for Deithland:

Tier V
Developed backwards from the technology that brought us the fabled Pyrehulks, these soldiers of Deithland compose its toughest frontlines. Utilising smaller versions of Pyrehulk frame technology, they are encased in steel like none before them, and as their brethren more than hold their own at range- they become specialized in protecting them, and thundering down the enemy as they approach rather than run away.
Grenade Pistols (Inspiration Helldivers 2) provide few (2-4) but powerful rounds to be fired by the unit before the enemy has made contact, devastating cohesion and potentially opening them up for a counter-charge. Regardless however, the units broad and tough shields provide tremendous melee and ranged defense, able to withstand a considerable amount of punishment due to increased thickness allowed thanks to the steam frames. Axes are the preferred melee weapon of the unit, dealing equal parts Base and Armor Piercing damage (represented by the Blunt/Cut damage potential of an Axe) that is sure to bring down all but the heaviest of opponents with ease.
If a line need be held, these men will hold it without question or fail.
Design Ideas
To represent their Elite status, they could have brass- decorated armors and less cloth above the waistline, instead presenting bare steel throughout most of the model. Reusing some downscaled versions of Pyrehulk models and pieces of Deithguard models would work wonders.
In terms of stats, they should be very heavily armored (115-130), feature extremely high Melee Defense and solid Melee Attack.
Uniquely, I would suggest maintaining the Ultra unit scale size at 120 men with a considerably higher HP pool, instead of dropping the number of entities to 100 or 90. This is so that they aren't a direct replacement to their middle-tier brethren, as you can have less of them (especially with how expensive they should be), and do the job of the current shielded infantry with less units. This would allow for greater variety in army compositions.
Bonus against Infantry (Melee Attack, +5) makes the most sense to me to assign to this unit.

Tier V
Developed backwards from the technology that brought us the fabled Pyrehulks, these soldiers of Deithland compose its linebreakers. With greater carrying capacity and greater funding comes bigger and better weapons. Armored to the limits, these men bring with them a bastardization of a Greatsword of the old world and a Longrifle, specializing in softening targets before they come into contact with the frontline before manoeuvring to the flanks of their shielded brethren to cut down the enemy while they hold them in place. Dealing mostly Armor Piercing damage and a good deal of it, the unit is pressed to engage the most dangerous foes the enemy can muster against the more fragile components of Deithland's armies.
Should the enemy present a strength, these men will turn it into a weakness.
Design Ideas
To represent their Elite status, they could have brass- decorated armors and less cloth above the waistline, instead presenting bare steel throughout most of the model. Reusing some downscaled versions of Pyrehulk models and pieces of Deithguard models would work wonders.
In opposition to the Grenade Pistols and Shields variation of the unit, I think a lower (90) Ultra unit scale entity count works best for a 'Hammer' type use unit like this one, they should have very heavy armor (115-130), lowering this somewhat in exchange for speed (they are meant to go for flanks after all!) if deemed reasonable. Bonus against Infantry (Melee Attack, +5) makes the most sense to me to assign to this unit.

Tier V
Why improve upon perfection? Why, because we can! The Pyrehulk revolutionized the way battles were fought, and how Artillery could be handled- it is time for this to go further.
The Emberhulk is a scaled up, refined version of the Pyrehulk, reserved for those elite soldiers that have fought and survived countless battles in the older generation suits. The Volley Gauntlets are back, and better than ever- firing faster, and hitting harder, thanks to advancements in propellants and reload mechanisms. Shields now adorn the left arms of the mighty mech-suit. Broad, thick, and tough as castle walls, they provide directional protection from missiles like no other (80% frontal small arms fire deflect chance?) and a defense that is nigh impervious. When in melee, the weapon of choice for the Emberhulk pilot is a mighty Hammer, in honor to the workers that built these wonderful machines (20% base, 80% Armor piercing). With improvements to the steam mechanisms, one need not worry about blunt force not being enough- the oversized monsters will be squished down in the end.
There is no foe the Emberhulk cannot fell.
Design Ideas
To represent their Elite status, they could have brass- decorated armor, and perhaps a greater number of insignia along the suit.
Being roughly 1.25x the size of the Pyrehulk (give or take) would work wonders, along with having their entity count reduced by 2-4 units. They should have extremely high armor (140-160), Melee Defense and High Melee Attack.
Cost should be through the roof with these boys- only fielded in large numbers on something like a Royal Guard contingent or somesuch.
Charge Defense (all) makes a lot of sense for such a heavily protected unit, combined with Bonus Against Infantry (Melee Attack, +5) and Bonus Against Large (Weapon Strength (+5) makes sense to me.

Tier V
Why improve upon perfection? Why, because we can! When the Emberhulk was first devised to uplift the greatest soldiers of the Pyrehulk korps, serious considerations had to be made, a Shield was added to the Volley Gauntlet variation- drastically changing its utility on the battlefield.. but the Fusilaxes? As they say, with a bigger budget..
With their weapons made wholly of steel, the range of the Halberdrifle Emberhulk was increased greatly, and so was their ability to present such an enormous weapon in defense. Any enemy that charges into a line of these modern suits will greatly regret it, as their charge is turned against them. At range, even the thickest of armors will struggle to maintain true in the face of the thundering of rifle fire, and in melee, the exceptional range and heft of the Halberd portion of the weapon cuts through the largest of foes with ease. The only 'struggle' if it can be called that these metal behemoths will ever face are large swathes of fodder.. but Deithland's armies are far from one-dimensional, and their brethren are sure to deal with such rabble.
Size will do you no favors here, heretic.
Design Ideas
To represent their Elite status, they could have brass- decorated armor, and perhaps a greater number of insignia along the suit.
Being roughly 1.25x the size of the Pyrehulk (give or take) would work wonders, along with having their entity count reduced by 2-4 units. They should have extremely high armor (140-160), Melee Attack and High Melee Defense; the inverse of the Volley Gauntlet really.
Cost should be through the roof with these boys- only fielded in large numbers on something like a Royal Guard contingent or somesuch.
Charge Defense (all) and Charge Reflect makes a lot of sense for such a heavily protected unit, combined with Bonus Against Large (Melee Attack, +8) and Bonus Against Large (Weapon Strength (+12) makes sense to me- one can compensate for such large bonuses by reducing the base amounts of both- these are a specialized unit, and so they should struggle a little against the rabble.


Tier IV-V
The venerable Chemlancer is an expert at dashing in and out of combat, providing devastating damage to the enemy's rear line before disappearing in a cloud of Cinderwind. But there is yet much more to give.
With mechanical horses, armored to the utmost, these deceptively fast and heavy riders bring a very different kind of thunder to their charge- where the Chemlancer disappears in a cloud of Cinderwind, the Chemknight stays to fight in the thick of it. The sheer mass of the unit crushes through most infantry like cannon shells through wooden fortifications, but should that prove insufficient, any foe not equipped with a sharp spear will be in trouble. The Chemknight's kit is designed to keep them alive in the thick of battle even against specialized infantry, with weapons coated in poison, more than capable of crushing through heavy armor, and Cinderwind canisters strapped to their harnesses, ready to blanket the battlefield. Enemies trapped in combat with Chemknights will struggle to maintain a foothold for more than a few moments.
If an enemy need be engaged, and kept there- the Chemknights will handle it.
Design Ideas
To represent their Elite status, they could have brass- decorated armor alongside considerable colourful insignia/barding, which could be borrowed from Bretonnia or the Reiksguard.
Mechanical mounts can be taken from Nuln easily enough, and it shouldn't be impossible to adapt Reiksguard armor to them.
Armor should be very high (120-135) and speed should be serviceable (80-90), if a stat exists for acceleration, it should be lower, but once they get going- it should be difficult to stop them. High Melee Attack and Defence are both hallmarks, and Poisoned weapons is crucial as a trait- stacking both Cinderwind and Poisoned to severely reduce an enemy's combat ability and keep them pinned.

Well, that about does it[/b[For now at least, something about Deithland just makes my mind race with ideas- I left a few out to keep this a bit more brief than it otherwise could have been, gods know it's already plenty to think about.. But, even if a little unrefined and only specifying certain aspects of the units, I think they're neat enough to suggest.