I always thought Tyranochromis macrostoma would be a kick a-- hap to have. Its name roughly translates to big mouthed terrible cichlid. These fish look like fearsome predators. Checked out profiles from different sources before and noticed they have alot of variation in general appearance. Never saw one I didn't like though. Buccochromis species are great as well. Also dimidiochromis species can be brought back into consideration if you go all hap. Fronts probably couldn't compete well for food or space with any of these fish though. If you decide to do this tank, I wil forever be envious. I agree with GTS. All hap tanks are too hard to find. Good luck and please tell us how it turns out.