Toyota asks for help deciding plural of Prius

Toyota is trying to make Prius into a family of vehicles, not just the top-selling hybrid. At the North American International Auto Show this week, the Japanese automaker unveiled two new Prius derivatives—a smaller version and a slightly larger version. There is also a plug-in version of the Prius coming. And there is talk of a Prius-branded van, too. The problem, though—or the opportunity—is what to call more than one Prius. Priuses? Prii?
  It reminds us of an episode of Taxi in which the cast was watching a cable feed of a Delaware state legislature debate about whether to be called Delawarians or Delawarites.