Sell the rt 10d, it will only hurt a setup with a real subwoofer, not help.
If you want sheer output, I will offer some suggestions. If you want the highest possible output at the deepest frequencies, I recommend you push your budget a bit and get the
Elemental Designs A7-450. Its 1650 shipped, it weighs 300 lbs, and it is large. I'm sure that could pump out 20 hz at monster SPLs. If you want something more manageable, check out the
Rythmik FV15hp. It won't be the deep frequency beast that the A7-450 is but it still has an enormous amount of output.
If you are not concerned about deep frequencies, ie stuff below 30 hz, I would go for dual Epik Empires or dual
Elemental Designs A7s-450 s. If you want something more balanced between the deep and upper bass frequencies ie a flatter frequency response but not quite the overall output, go for dual Hsu VTF3 mk4s, dual
Outlaw Audio LFM-1 EXs, or dual SVS PB12 or PC12 NSDs. I think its also worth looking into what Chase Home Theater has to offer.
Any of these setups will hilariously outclass your rt 10d sub.