(For anyone even remotely interested in DIY type stuff, it's a fascinating thread)
After contacting the owner of the company who makes the amp boards(Tom, who seems like a really nice guy), I ordered a large toroidal transformer (1000VA), heavy duty power supply, and two amplifier modules which should output 500W each easily when bridged. Since they are Class D, they are much more efficient (>90% vs 50-60% for class A/B) and should put out much less heat. THD numbers look really good too. I should be getting the parts by this weekend and will do a quick assembly first to test things out and see how it sounds. I'll let you guys know how it goes.