That's what the Jaguar CX-75 was going to have. These guys do them as replacements for "traditional" gen sets too. We used to make the carbon sleeves which allow a generator to run at 100,000rpm directly coupled to the turbine.
https://www.bladonmt.com/
Why better idea, turbines are more efficient, simpler, quieter, smaller, lighter, also don't vibrate etc etc. They can also run on almost any liquid fuel.