Tanganyika Shellies, an example would be Neolamp multifasciatus, Neo brevis, Lamp ocellatus, Melaegris and a few others.. about 4 to 5 shellies total they stay around the 2" mark so a 10gal could work as long as your loyal to you water maintenance..
It all really depends on the species but I dont know that I would do more than 2. If you go with Multifaciatus then they arent as bad as the others, but other species you want only one male or you will run in to problems.