yeah hes gonna get big bro, and i agree with the pond idea. one option is to build an indoor pond out of plywood. 4x8 pc of plywood, make it a couple feet tall, put a spot in the corner thats out of water, and make the rest get gradually deeper. that way he can have some "fun" (if turtles have fun, i dunno) chasing live feeders if u go that route. a veiwing window would be optional.
as far as tank mates? another snapper? those guys r evil. i had one in a 75ft x 15ft x 9 ft deep pond @ my parents. i originally stocked it with catfish from fishing trips, and left over goldfish and bluegill that were intended for bait. the catfish got decent size, the goldfish slowly disappeared (also used dog food and some kinda fish food) - ne ways, one day, we caught about a nice 7 pounder and put it in the pond. about 4 hrs later i went out there and it was dead, floating, with about 5 bite marks out of him. so i set out a jug line with a hotdog, let it sit over night, next morning pulled out a 2'+ snapper out of the pond.
moral of this story?
THEY DO NOT PLAY WELL WITH OTHERS!! but you get a big enough space they should do ok with other snappers i would think
