Fuel cells are a real load of crap. They've had plenty of time to mature as a technology, but haven't. All of the battery chemistries are recent compared to the life of the fuel cell.

There's supposed to be an advance in solar cells coming this year (like, it was developed and is going into production). Maybe that will be the answer for where power comes from.

Now, all this said, someone pointed me at a new idea which looks interesting.
http://www.theaircar.com