[Uh-Nu-Buh]

It's a great idea, but the way you portray it would require the developers to do it, and I believe it would be a major effort.

Another way to do it would be a mod with a special Place called The Forge that allowed 4 new units: x, y, z, and p. You could have several special places:

Iron Forge: several types of light infantry (not rare)
Steel Forge: sevearl types of heavy infantry (rare)
Adamantium Forge: several types of super heavy infantry with low encumbrance/fatigue(super rare)

The Corral: sev tps of lt cavalry
War Corral: sev tps of hvy cavalry
Circus Corral: sev tps of super cavalry like elephants, rhinos, and giant mutant humans a la freak lord

Archery Range: sev tps of archers
Mech Range: sev tps of xbow archers (pistol, auto, hvy, small arbalests)
Siege Works: catapult units, arbalest units, etc.

Likey?