If this can't be done with a config file or console vars, it could probably be done with a memory hack. If the HUD can be fixed, I'd be willing to give it a whirl.

I did some digging with this today, but my lack of experience with Flash is holding me up. There's a load of .gfx files for the hud which I had a go at decompiling/looking at. There seems to be a Constraints.as file embedded in class3hud.gfx, which has layout/scaling functions. It looks to me like this is what would need tweaking to fix the HUD for non 16:9 aspect ratios, but it needs someone more familiar with Flash/ActionScript to implement it, since the whole thing is doing my head in atm.