Sams, I would recommend the same subs mentioned upthread, and base your decision on overall room volume you're trying to fill. Multiple subs is not about added output, but smoother response over more of the room. A pair of sufficiently powered 15's from the usual suspects would be a good place to start. As for equal loudness back at the billiards table, perhaps a pair of zone 2 speakers back there.
fmw, I completely agree that actual measurements trump any calculated guestimate, but the OP doesn't yet have an spl meter, and probably lacks an appropriate multimeter too. But it's still just a guess. I used the myhometheater calculator which gives about 4db/m loss with distance, so there is what seems reasonable room gain factored in. Without it, he'll need 300 w to hit the same spl at the same distance, and that's well in the red for both amps and speakers. He could very well be clipping his amps when trying to listen loudly, even with some room gain, particularly if trying to achieve similar volumes back at the billiards table! LOUD seems to have him bumping up against the limits, amp, speaker, or both, but at least he's taken to heart "if it sounds bad turn it down immediately" advice. Proper subwoofage seems the obvious low hanging fruit, and would likely transform his enjoyment enough that he could live happily within the limits of his Revels.