Neolamprologus brevis will do great in a 10 gallon tank. A pair (who share the same shell so you can often easily find a pair at the LFS) are ideal for your tank. Use aragonite/crushed coral for the substrate to keep the pH/KH up and you're good.
N. multifasciatus would also work, but they breed like bunnies so you'd need to sell/give them away fairly soon. Get 4 and you'll likely have one breeding pair.
Eric