May I suggest the Sherman Firefly as the perk vehicle? The sherman would (imho) be well worth modelling, as with only minor modifications to the model/graphics later other versions of the Sherman could be added:
Sherman Calliope - multiple heavy rockets
Sherman 75mm - roughly same as Pz4
Sherman DD - amphibious (complements amphib troop carrier?)
I'd also suggest the "hanomag" series of German half-tracks, (Skfz 251) as these carried a huge variety of weapons from Mg's to Pak40 AT weapons via flamethrowers and searchlights.
Clearly AH is principally an air-game, but for some economy in production of future vehicles, this might be a sensible way to progress?
Originally posted by Lephturn:
Fighter perks can only be spent on fighters, bomber perks on bombers, and vehicle perks on vehicles. I'm sure there will be a perk vehicle included in the future for you to spend points on.