According to industry coverage, Toyota is unveiling the Prius V, a wagon-type model larger than the current version, at the North American International Auto Show. This, plus a concept version of what the 4th version of the classic Prius might look like.
All of this, and the plug-in version of the Prius is now being tested at universities, government fleets, and other limited markets for awhile until all kinks are worked out and it's ready for mass market.
This makes me think of the mysterious Toyota fuel cell car that's supposed to come out in five years. Perhaps that will be a fuel cell edition of the Prius? That's what I would do if I were a decision maker at Toyota. The company is counting on the Prius brand being considered the greenest of the green cars, and will be offering several different versions of the Prius, as if it's becoming its very own brand almost separate and distinct from Toyota - similar to Toyota's Scion and Lexus brands.