Desmophile please check out these guys - Bladon Jets for possible future powerplants to drive generators. It's run by a very good friend of mine Chris Bladon, his twin brother Paul sadly died a few years ago but Paul spent years finding a way to make the micro turbine parts small enough - it was a manufacturing/design process that the big names in turbine manufacture had given up on. They have been involved in hybrid car prototypes and other applications where the size of the drive motor is the most critical thing.