I may have waited too long... looks like nobody has the Rockfort Fosgate P1000X5 amp in stock. I guess I'll wait a few days and then maybe re-evaluate my plans. I was hoping to buy one today but maybe someone will get them back in stock, though Crutchfield's showing a month to get
Another amp that's caught my eye is the JL Audio XD700/5 it has the balanced differential inputs as well, and the 4 channel section seems to be all the power I'd need.
http://www.crutchfield.com/p_136XD70....html?tp=35808. It would mean going back to a 2 ohm setup for the sub, but would 300W RMS be good enough to run the JL Audio 10W3v3-2 driver?