Holyfish has some great suggestions! that Ivoryhead won't do well if there is too much agression. Watch out with the placidochromis, Milomos are mean and big, and Phennochilus are a favorite but can get big as well.
As I said, I like Holyfish's suggestions... maybe do a Red Empress or Phennochilus or both.. maybe a Stuartgranti Peacock like a Ngara or Blue Neon... a A. Koenings/Mbenji might work out. I think every tank needs a good Rubescent peacock. Midnight peacocks are cool and stay small... Don't overcrowd, you can overstock, but overcrowding doesn't make that nice of a tank and can easily be done in a 75g!