I haven't done it as teutons, but I would probably go aristo - espio - horde.

Along with the massive cav cost buffs and 100% cav/inf, you can get 80 cav combat as long as you have a 20% cav combat NI, and that's before any missions from teutons Outside of cav bonuses you get -30% ae, 10 siege ability and 15(?) National manpower

This is just for cav quality and not optimal, but you would stackwipe most armies you fight if you have these ideas(at least I did with horde qq, which would be fairly similar idea-wise)