Brant, excellent write up there! Maybe you can verify something I'm going to say here because I'm not 100% sure if this is true.
Correct me if I'm wrong here but I don't THINK that leopards are in fact another gene at all. I don't think they are ALLELIC with pieds. I thought I heard somewhere that the first leopards came out of a clutch containing pieds. So it's not like saying that a new leopard came out of Africa and pieds came from that. No. An existing captive snake was bred and leopards came out. Correct me if this is wrong info.
If what I say is correct then pieds would be considered co-Dom in my books. I have 2 het pieds with Leopard like characteristics but are surely no leopards. I know some people think there is no true recessives I'm ball pythons because they can pick hets out very easily in Clutches. Much like brant said.
Me, I don't really care about the morph labels in balls. After all, all the co-doms are incorrectly named. They should be incomplete dominants. So there are inaccuracies built in to this whole industry anyways. Whatever the case, Leo's and pieds are always awesome!