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.

Parasound JC1's.

Bridge a pair of Mcintosh Mc 2500 or Mc 2600 amps together. 1 to 1.2KW of power.

Krell 700cx; 1400 Wpc into 4 Ohms.

By the the JC1 won't do that, 800 Wpc perhaps.

Steve -

Per the Stereophile review the JC1s measured:

585W @ 8 Ohms
1154W @ 4 Ohms
2255W @ 2 Ohms
4.2kW @ 1 Ohm

Google it and you can see the tests. Krell is another great choice!