Well, you have a few to choose from.
Might be able to get away with 2 pairs in a 29gal?
Neolamprologus multifasciatus
Neolamprologus meleagris
Neolamprologus hecqui
Neolamprologus brevis
Neolamprologus calliurus
Neolamprologus pulcher
Prob. do a pair of Lamprologus leleupi
Pair of Neolamprologus brichardi
That should get you started. I personally like the Neolamprologus multifasciatus the best.