Ah.... yeah there's a thought pm, didn't think of that....
(goes off to try something)
@DsRaider - try this mate:
<Description>Horses grant your units more speed in combat and in travel and make them immune to being knocked prone.</Description>
<Provides>+5 Defense, harder to hit</Provides>
Give it to a unit.... should lift them horse height of the ground. Change the item <Scale> to make them higher.
Fairly sure that's exactly what you want.
Edit -> With that example, the guys feet will slide around slightly now and then. To improve it I think you'd want to replace the "MountedHorseAnimationPack" above with a custom one and remove the horse animation that causes the problem. Should be fixable though.
This could be cool if it works.
Another Edit -> Just did some more testing, could be a few things to iron out but I think it works. *Might* need to add a modelfile back in.. I think there might be some weird things happening without one... needs more testing.