My thought was:

-20% bullet spread (more accurate)
-20% fire rate
-33% clip size (from 12 to 8)

effectively a longer range version of stock, but the lower fire rate and smaller mag means it can't just be spammed the way stock can

+ 10% damage

- 10% firing speed

+ 5 max hp on wearer

- 50% damage if ubercharged

+ 1% damage vulnerablity on wearer

+30% fire-rate
+1 clip size
-30% reload-speed

+50% more accurate
+15% more damage
-20% fire rate
-33% clip size

+20% fire rate
On last hit in clip: One target at a time is Marked-For-Death, causing all damage taken to be mini-crits

- 50% clip size
- 20% ammo
-10% damage
No random crits

HUG-DEALER I love your idea but add 15% or 20% extra damage to make it more worth using then we go a nice new multi class Weapon.

burst-pistol with 21 rounds in the clip (it's 21 so that it fits with the three round burst)

has medium level recoil

landing three headshots in one burst marks the enemy for death

does 5% more damage

15% longer reload

100 reserve ammo (200 for engie)

Stat suggestion:
Pros:
- 90% bullet spread reduction
- 50% reduced damage fall-off
- 5% damage increase

Cons:
- 33% reduced magazine capacity.
- 60% reduced firing speed.

* I might recommend a heavier, more recognizable, and distinct sound to the gunshots so as to be appropriate to the weapon's fire rate and usage as a long range harassment tool.

it just simply reskins & resounds the normal pistol thats, like the luger

weapon reskins in team fortress 2 have always seemed like a strange case to me

Upsides:
On Hit: gian 1 Streak
At 5 Streak: the next shot is a crit and reset cStreak.
15% faster reload speed
On Kill: gain 25 health.

Downsides:
On miss: lose 2 Streak.
15% less damage
10% slower fire rate
no random crits