Need at least 900wpc in 4ohm

You can do this cheap (+ runs quietly!)with the Yamaha P7000S:

http://www.yamahaproaudio.com/global/en/products/poweramps/ps_series/specifications.jsp

If you would rather have Class D (runs cool and also runs quietly!):

http://www.crownaudio.com/xls-drivecore.html
You could get 2 Crowns and run them in bridged mode if necessary.

Perhaps just a single amp would be enough if you get the largest Yamaha or Crown.

I disagree with Atmasphere's assertion that there are no particularly musical amplifiers that provide in excess of 500 Watts into a given speaker.

Me too. I would also like to see the complete list of >500wpc he has actually heard and compare it to the complete list of all 500wpc amplifiers ever made. And why 500wpc is a magic number where everything over that is not musical. Just silly.

Thanks for the explanation Atmasphere. Maybe this weekend if I have time I'll put my 25wpc single ended SAR Labs Little Wally monoblocks back in and check them out. Switched over to something greener for the purpose of saving money (+ higher power output and balanced inputs) since I like to leave amps on 24/7 but I guess I should put my old amps back in and see if maybe I'm missing something.