400W amp under $2000

Also less than 10 years old when built.

How about a Behriner EP1500 for $299.99?

1400 watts in bridged mode and many audiophiles on the Magneplanar forums rave about them.

Apparently the fans are a bit noisy but can be switched with quieter ones.

For < $300 bucks, the build quality won't remind you of a Rowland.

I am going to get two of them for biamping experiments, just for fun.

How about a used pair of Aragon Palladiums? Any of the three versions--Palladium, Palladium II or Palladium 1K would meet your needs; although you're probably looking at the P or P II but not the P 1K due to price concerns.

And they're NOT made in Communist China.