So, we got him a drum set for Christmas. It has a kick drum (bass), two tom-toms, a snare, a crash cymbal and a hi-hat. He already had one snare, so he's using that as a third tom-tom. He does miss the third cymbal, but he got some money for Christmas, so he'll save up and get that one on his own.
Thanks again for the input. There is now a lot of awesome jamming going on in our basement!