Although the current system will only power the AC unit, and is for all intents and purposes is just for show, this is definitely a step in the right direction. The California company SEV has created a solar panel system for Toyota Prius (2004-2008). This system takes 2-3 hours to install and boast of a 29% improvement in fuel efficiency. If you are interested this system will set you back $2K to $4k, but it should pay for itself in 2-3 years.

     Toyota is on the right track and hopefully as technology improves the impact that solar panels have on our energy consumptions will increase. Judging by the advancements in recent years I would not be surprised to see a road vehicle by 2020 that is capable of being powered by the sun entirely on a sunny day.  Possibly this will be done by solar charging stations or by munted panels that charge the batteries when the car is parked.