At the 2011 Detroit auto show, the Prius family grew threefold, adding a plug-in model, small hatch and a family mover. The latter, called the Prius V, will be the first model to join the regular hybrid model later this summer. The Prius V is supposed to be a more accommodating place for kids and cargo. As Cars.com editor Joe Bruzek points out in this video, the backseat is roomy. But will Prius owners want a larger vehicle that takes such a heavy hit to fuel economy?