IDQ's might fit the bill pretty well, or an idmax if you can find them. Much lower power requirements than many of the subs that have been listed so far. Effeciency is a good thing
If You are close to me you can pop my rl-p into a box and see if you like the sound. I live in Snellville-Loganville. Work of of Howel Mill Rd. In ATL.