It's a sure-fire bet that Toyota will unveil its upright Prius MPV at the North American International Auto Show in a couple of weeks, a rather more roomy and practical version of the hybrid that really started it all. And, of course, the plug-in model we tested in October will be surely rocking the floor. Now we're hearing that another as of yet unreleased Prius will be on display, simply referred to as a "Prius concept vehicle." Concept cars of course range from the mundane to the insane, and kn
