I own the Mirage BPS400, bought it from Tweeter for $799 (originally $1299). It has (2) active 12 inch drivers and a 400 watt amp. It's rated down to 16 hz. I also only use it for movies. It really rocks the house, I don't see how you could do any better for the price. Nevermind, I just checked the height, it's 21" high. I use mine as an end table, 12 feet away from the TV. This may be too much bass for you. If you're planning on enclosing a sub in a cabinet, it will have boundary reinforcement, which means you won't need a very powerful sub.
John
John