Those of you who are engineers in the black arts, here is a little brain fart I had.
Get Streachy's little class E rig. He says ten watts (that's the fuse).
Now, go yeah and get a 300 watt class E design and the transmitting caps etc, you will need. If you build a 50 volt dc supply supper, but saves time pick one up. Many commercially out there.
Realize the Pirate trade can just as easily go to basics and use ROCKS (crystals)
The Little Starter Transmitter can be made to work about anywhere. Now take a peak at the low pass filter. Yes, but if you use this as an exciter, no way you need worry about harmonics in exciter. You filter those in the final class E 300 watt amp .
Modulator? Well, if you can find a 200 watt class D amp. Yes these amps for audio on Ebay else where for LESS than 100 USD.
Now the creative part, bridge the stereo channels. 100 watts per channel becomes 200 watts of audio, enough to even over modulate a 300 watt class E. But, you need an audio quality transformer. Or use some other creative way to series modulate the class E stage.
Output matching Pi or yes even a RF transformer to 50 ohms nominal.
The FETS at between 300-500 watts present a damn close output impedance at 50 volts of 8-4 ohms. Idea for high power audio amps and this you will recall is speaker level impedance.
Upshot.. transformer turns ratio damn close to unity, i.e. 1 to1
So that's my naughty thought.