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.
