Aside from Cyprichromis spp there are also the Tang killies, though they're not easy to find and usually expensive if you do. All of the open-water fish need at least a 6' tank, larger is better.
I did have some juvie V. moorii that seemed to be less inclined to hang around the rocks than many other species. They do get quite aggressive when spawning, similar to brichardi in that respect.