Since everyone is throwing out "off the wall" suggestions, why not just do what I did. Just go to your LFS and buy what looks pretty to you, as far as cichlids, that is. Here is the stock of my 40 long:
5.5" Red Zebra, 3" Red Jewel, 4" Blue Malawi, 3.5" M. estherae OB, 4" M. Auratus, 2 - 3" Krib, Breeding pair Convicts, 5-6 baby Convicts ranging from 1"-2.5", 3.5" Firemouth, 5" Jack Dempsey, 1.5" snow white socolofi, 6" common ple*co (whom is recovering in my 10g community from a BAD injury and if he does recover/survive, he will then only be a 4" (pretty sad, check out his thread
http://www.myfishtank.net/forum/showthread.php?t=34333)), oh and a Gold Mystery snail.
Anyway, what I'm getting at is that even though most say not to mix Africans & SA, CA, etc., I have been quite successful with my mixed tank. You get the best of all worlds! They all seem to get along great for the most part. Yes, there are occasional fights, but even in a species tank you're gonna see that. The secret is obvious, get 'em all together while they're all young. Your Jack Dempsy will leave 'em alone. They're generally pansies anyway.
Just my couple-hundredths of a buck!