[Amps] Linearization problem

[Bill Turner]

Instead of driving the amp with RF, I would suggest doing it
digitally. Some years ago I toured the KFI transmitter in La Mirada,
California and saw their Harris DX-50. It is a 50 kW AM transmitter
that creates the AM signal by switching in and out a bank of 250 watt
modules at an RF rate. There is no "driver" as such, just a switcher
which switches the modules in accordance with the audio signal. It was
quite impressive. 

Perhaps some variant of this or a pulse width modulator scheme would
answer your question. 

73, Bill W6WRT