I believe there are no cross-breeds simply because they just aren't made yet xD.

Like cat guys are "rare" but now they are all over. Au Ra turned up out of no where but were pretty much nonexistent before besides Yugiri. And she used Miqo'te body and animations. Once Au Ra were finished, they had their own bodies, faces, and animations and Yugiri used that instead.

I believe this will be the case with cross-breeds.