Request for opinions on fish for small Malawi tank

After a couple years of a community tank, I am thinking of setting up a Lake
Malawi aquarium in my 46 gallon bowfront (36" long). My concern is about
the size of these fish. I looked at many Cyrtocara species, as mentioned in
"Aquarium Designs Insprired by Nature", but they seem to be mostly 6 - 8
inches. I fear that may be a little big for my tank. Can anyone recommend
particular Malawi species that are readily found and not too big for this
tank? I have found a few in my books that are maximum of 5" or smaller, but
I don't know how readily I will actually find them in the LFS.

Also, is it common to get one of each species of fish? In the book it
mentioned that difficulties can be encoutered when having multiple males and
I have noticed that the African lake tanks I have seen all have one of each
species.