My current thoughts on an alternative energy car is a Tesla turbine powered by CNG or Propane driving a genset. Then, your standard electric motor drive. The problem with turbines has always been trying to build a transmission for a engine that doesn't like to change speeds much. But, running a genset should be easy, (technically easy) but there will be a lot of playing with fuel flows, inlet types and how to handle the heat, etc...

For actual transport, i feel we should start looking at mono-rail / i-beam tracks. And put automated cars and delivery pods on them. Trains and cars are really obsolete, except that the existing infrastructure, there is far better ideas.

All i can say is that the future will be interesting.