Toyota have just announced that they are developing dye-sensitized (ie not silicon) solar cells for use on cars and homes.

http://www.greencarcongress.com/2006/05/ai...i_and.html#more

They can be any colour, so could be mounted all over the car. Graetzel cells are also 60% cheaper than silicon cells but still reach 12% efficiency in sunlight.

Could recharge the batteries of a PHEV Prius very nicely indeed - up to 4 kWh per day I reckon, which would be enough for 16-20 miles EV range per day from solar alone.

They intend to have a practical version in use in 4-5 years time.