Need help choosing an Infinity SSW-212 replacement?

My Infinity SSW-212 started muflling sound at lower frequencies so I checked for tears but couldn't see anything. I just dropped it off at a local shop to see if they find anything repairable on the unit. I'm not optimistic and have been exploring possible alternatives. I'm curious what class of subwoofer in today's market would be an upgrade over this model? I have a relatively crappy room (loft approx. 30' wide x 12' deep x 9' high open to the stairway at the left and great room to the rear - 4' high wall). The Infinity did a "decent" job with bass given the horrible room conditions and space is not a big constraint given the size of the SSW-212. Anyway, looking for suggestions to pair with the following gear:

Def Tech Mythos 1, 2 & 3 for LCR and surround
McIntosh MC 7205 amp driving all 5 channels
Integra DHC-80.3 pre/pro

I've looked at everything in price from the Outlaw LFM-1 EX to a Seaton Submersive so while price is not the number one factor, I am interested in finding the best value considering where I'm coming from at the moment. Also, I'm leaning more towards thinking about the future than how good this setup might actually sound in the current space so resale value might be a consideration for when I move to a different space. Finally, since I just got the Integra, a dual sub configuration for this space might be worth considering. Thanks in advance for any recommendations!

EDIT: Guess I should've mentioned that I use this setup for 90% HT and 10% Multich Music. I've also got a B&K Ref 50 SII that I use for stereo but that's pretty rare these days.

Thanks for the response guys! I've had my eye on the HSU VTF-15 (single & pair) as well as the Rythmik FV15HP (single or pair although a pair is starting to get expensive!). Don't know much about Chase or Funk so I'll look into those as well.

Reading through some of the shootouts, the Captivator seems to have mixed reviews (as compared to a Seaton or any other +$2k option). FWIW, I would also add that I prefer clean, deep, distortion free bass over air moving, chest pounding bass that might suffer on the low end with higher thd.

Also, how does the SSW-212 stack up against a more modern sub?! This is the only sub I've owned so maybe two Outlaw LFM-1 EX's would be a noticeable improvement?! Just curious...I would say my budget "could" stretch to $2k or so but if I could get a much more noticeable improvement over what I'm used to for less then I'm interested in other alternatives.

Thanks again Jim! The SSW-212 is at least 15 years old. It's basically 2 12" woofers stacked and the specs are as follows:

Frequency Response 25Hz - 120Hz
Crossover Frequency (ies) 40Hz - 120Hz continuously variable
Power Output AMPLIFIER - 300 watts RMS
Woofer Dual 12" IMG
Weight 72lbs. NET
Dimensions (H x W x D) 20-1/4 x 31-1/2 x 11-1/4

Doesn't seem to be too difficult to do better than this but when you look on E-bay at what these are going for it's pretty astonishing. Any idea what makes them so unique considering parts are really no longer available?!