Toyota's Prius has remained the best-selling hybrid of all time even as competitors like Ford and GM step up the competition. But the Prius can't do it all--for anyone with a large family, it's just not big enough. Perhaps that's why Toyota is hatching a plan to produce a line of Prius vehicles, with either a wagon or SUV first in line for a mass rollout.

Few details have been released, but Toyota is reportedly thinking about installing a lithium-ion battery pack in the vehicle--a surprise considering that Toyota has repeatedly claimed that lithium-ion batteries aren't cheap or reliable enough for mass use. The new wagon/SUV will be bigger and heavier than the Prius sedan, and will likely have a larger power system (read: a larger battery pack).

Beyond those scraps of information, Toyota is staying mum. The new Prius could be a plug-in or a regular hybrid, and pricing is still up in the air--though Japan's Yomiuri Shimbun newspaper says that it will retail for about $22,000. But whenever Toyota decides to release the new, larger Prius, we can expect a rapid increase in the number of hybrid-owning soccer moms.

[Via Green Car Advisor]