well - yah, it doesn't have to be much power, I was only wanting about 10W of heat at this stage. One of the most important things is it's able to be made cheaply and reliably. I't doesn't have to be a square wave, a square wave is just preferable as it's kind of like a higher duty cycle. I have thought about RF amps but cant seem to find any small cheap ones that can do that voltage.

So yah - ideally i'd like to transistor (bipolar or FET) switch it but it's just getting the Gate/base voltage up there.

thanks