every since i saw malawis in my lfs i wanted some, but tanks size hasnt allowed me, so i thought about getting the largest i could fit, an 80cm 33galon tank... and get tanganyikans, however research has shown that even for this tank size not many would be happy, so your tank would be limited to the small shellys, of tanganyika-- brevis and multifasciatus... you can keep a colony of the latter mentioned species... if i were you i would either get a bigger tank- like a 45 or 50 and keep tanganyikans-community(more choice in this tank size), or think about what other cichlids you can keep- ie, kribs, maybe some new worlds, the small shellys of tanganyika dont really have the wow factor for me, so if i wanted to keep african cichlids i wouldnt bother until i had a larger tank, its all about territories, you must get the longest tank you can and the deepest, height is irrelivant(to a certain degree), they have to have suitable territories to defend, and when they are ontop of each other then there is likely to be agression and stress, on your part, not just the fishes
good luck mate