Speculation about what models will join an expanded Toyota Prius lineup has run rampant since Toyota confirmed at January's Detroit Auto Show that it would add more body styles to the current five-door hatchback.

One candidate: the Auris Hybrid, effectively a hybrid version of the Corolla hatchback body style that's sold in Europe--but not in the U.S., where that role was filled until recently by the now-defunct Toyota Matrix. Another rumor: a coupe version.

Toyota Prius station wagon, from BurlappCars.com

Toyota Prius station wagon, from BurlappCars.com

Toyota Prius station wagon, from BurlappCars.com

Toyota Prius station wagon, from BurlappCars.com

Now more details have emerged on what will apparently be called the Toyota Prius Alpha, also called a  or "people mover" in Europe. It's a small 7-seater, just 11.8 inches longer than the current 2010 Prius.

A highly detailed rendering published in a Japanese magazine and reproduced by Motor Trend shows very similar lines to the guesses at a Prius tall station wagon that we wrote about last November.

Expected next March as a 2012 model, the seven-seat model of the Prius Alpha will be Toyota's first hybrid to use a lithium-ion battery pack. Today's 2010 Toyota Prius was supposed to launch with lithium cells, but Toyota's engineers bet on the wrong chemistry.

However, a five-seat model of the Alpha may retain the proven nickel-metal-hydride chemistry that Toyota has used in every hybrid since the first Prius was unveiled in Japan in 1997.

What remains unclear is whether U.S. buyers will be offered the 2012 Prius Alpha at all. Small minivans are hardly a huge segment in the U.S. market, with the 2010 Mazda Mazda5 (slightly larger than the Alpha) as the sole contender until Ford launches its C-Max as a 2013 model.

[Motor Trend]