With pi*Vin*modulation*headroom appearing on the MOSFET, then perhaps you're looking at a 500V FET.
I like the TO-247 IRFP450 MOSFETs, rated at 500V, 14A, 330mΩ Rds
Here's the datasheet:
http://www.ortodoxism.ro/datasheets/SGSThomsonMicroelectronics/mXrutyw.pdf
The input capacitance varies from brand to brand from around 2.2nF - 2.6nF.. I've used them up to 12MHz (25m), they feel very resilient, and they're very cheap from Digikey etc. At lower frequencies I've switched 350W+ with a single FET.
It probably doesn't qualify as "the best FET on the market", but I find them economical and reliable.