The genetics involved with frogs are totally different than tarantulas... also, if you mean crossing different species when you say mix-breed, that will just end up with one dead spider and one well-fed one.

Breeding pacs is very complicated, which is why very few people do it.

I don't know what specific morphs you're talking about, but I think a lot of the most unique frogs you see from samurai are mutants in the samurai blue line (someone correct me if I'm wrong, I don't really keep up with the genetics for pacs). In other words, no way to predict when you're going to get one or what it's going to look like.