Speaking with industry paper Automotive News, a Toyota insider reportedly said that the Rav4 and RX were chosen for the project over the likes of the Corolla because the larger models are better able to accommodate Tesla's battery pack (presumably a larger version than that used in the perfectly small Tesla Roadster).
While he would not confirm details of the prototypes, Tesla CEO Elon Musk appears confident for the project's potential.
“We anticipate range and acceleration exceeding that of other announced electric vehicles of this class,” Musk told Automotive News.
The reports follow news in May that Toyota and electric vehicle manufacturer Tesla have teamed in the formerly GM-Toyota owned NUMMI assembly plant in California, with Toyota aiming to expand its reach in the burgeoning electric vehicle market.
As part of the new partnership, Toyota and Tesla confirmed plans to develop new models and new technology for both brands, Toyota benefiting from the smaller Tesla's pure-electric focus, and Tesla gaining access to Toyota's resources and supplier bases.
While Toyota has focused largely on hybrid vehicles until now, new challengers in the electric vehicle segment such as Nissan, Mitsubishi, BMW and Volkswagen have put the world number-one carmaker at a disadvantage.
By teaming with the innovative Tesla, the Japanese carmaker could potentially leapfrog its rivals.
Speaking with the press last month, Toyota CEO Akio Toyoda expressed a frank desire for his company to rediscover its passion by working with the fast-moving Tesla.
"Through this partnership, Toyota would like to learn from the challenging spirit, quick decision-making, and flexibility that Tesla has," Toyoda said.
"Decades ago, Toyota was also born as a venture business. By partnering with Tesla, my hope is that all Toyota employees will recall that 'venture business spirit."
Tesla's purchase of the NUMMI plant will, according to CEO Elon Musk, involve "a couple of hundred million dollars" in preparation and re-tooling for production of the upcoming Model S electric sedan.
Part of the cost will be covered by a US$465 million loan from the US Department of Energy, along with around US$20 million in tax advantages through the California state government.
The Model S is expected to debut in 2012, and Tesla hopes to produce around 20,000 units a year. The NUMMI plant has the capacity to produce around one million vehicles each year - a capability likely to be embraced by Toyota as it moves to introduce electric vehicles to its consumer line-up.