Anyone attempted to change generals units?

Is it even possible? I'd like to see varied generals units similar to MTW1, even going so far as to completely remove the uber generals guards and replace them with standard troops. Perhaps increase thier armour value by a point or two over the standard unit to simulate that they would be the best equipped men of thier type.

For example: English would have mounted fuedal knights as generals guards, then followed by mounted English knights in the high period.

Byzantines, of course, would have Kataphractoi as they did in MTW1. Or even Varangian guard.

Danes, being more infantry based would have an infantry generals guard.

It's something I'd like to look into modding myself, but not sure where to start. Anyone have any advice?

Thanks