An established pair of Julies (though NOT the Gombe variant) is fine in a 29. However, aside from J. transcriptus, the smallest and least aggressive species, you will most likely have dead fish as they sort themselves out. I tried pairing off the Gombe strain in a 29, and ended up with a single survivor that had killed off the rest. Actually had the same thing happen in a 55, but by chance the 2 surviving fish were opposite sexes and did get along when I put them together in the 55. I eventually found a single fry that had survived on its own in the 55, then finally sold off the breeding pair. More trouble than they were worth IMO.
Otherwise, a breeding group (1m/3-4f) of ruby green Hap's from Lake Victoria are the only other African cichlids other than shellies that I would try to keep in a 29 unless you are moving in an established breeding pair from a larger tank. Most species of African cichlids need at least a 75, and bigger is always better.
