Why Is Toyota Stalling on Prius's Plug-In Battery?

If Toyota's hybrid system already has the ability to accommodate a larger battery for converting to a plug-in hybrid, making it possible to get up to 100 mpg, what are they waiting for? According to Bill Reinert, Toyota's U.S. engineer in charge of advanced vehicle planning, the large batteries don't yet exist. However, they're working on it as we speak.

In the meantime, a growing number of Prius customers are successfully converting their Priuses to plug-ins. Take a look at CalCars Prius+ plug-in hybrids, an organization at the forefront of a large initiative to build demand among highly receptive markets to encourage auto makers to produce 100+MPG "no-sacrifices" high-performance, clean hybrid cars, according to their website.