According to Nikkei, Toyota's apparently going to be equipping future high-end Priuses with Kyocera-built roof-mounted solar panels. Somewhat counterintuitively, the sun's rays won't be used to power the car itself, but will instead run the AC. It also sounds like your next solar-assisted Prius won't be around for a while, as the panels aren't designed in yet, nor will they be until early next year when Toyota starts work on revamping the line.