Check out the offerings from Sunfire. The tiny True Sub Jr. won't do the job, but the EQ probably would and the Singature would almost definitely work well. Might be hard to locate a new Sig from an authorized dealer for $1500, though... but it probably can be done. Might also look at Velodyne, but it would probably be even harder to find a decent matching Velo for that price.
RSW-15 would probably work... One of the new THX subs would do the job, most likely. Two would exceed the budget... Some of the offerings from SVS would match up. Probably should go with a plus series, at least... leaning towards the double driver box sub. Maybe even the Ultra.