Lionel, F1JRD has developed a state of art SSPA for 144 MHz that delivers up to 1300 Watt output with just about 3 Watt input.
Just a single brand-new transistor that was released in November 2010 from freescale is used in this PA. As this transistor costs just below 240 Euro (320 USD, 200 GBP) this results an amazing pwr/money ratio.
The PA is supplied with a cheap surplus 48/50V DC source. Lionel has presented the PA in the latest issue 4/2010 of DUBUS Magazine.
Data Sheet (PDF) New MRFE6VP61K25H Transistor