killer tank, i think you got the right idea with mbuna, very colorful, entertaining fish, but most will interbreed with each other, thats not necessarily a bad thing to some people though, i dont know what your preference is but if its a show tank then interbreeding may not be that big of a deal anyway, theres some really cool fish out there that are hybrids, but if u have your heart set on just a few species then i suggest you look at a few wholesale sites, and if you see a fish your interested in you can research the species