Lending at least an air of credence to this story is the fact that Toyota and Tesla are indeed working together in some as-yet-unknown capacity, and rumors of electric Toyota SUV mules powered by Tesla battery packs have abounded ever since the announcement was made. That said, some existing platforms converted to electric drive is a far cry from a completely new electric supercar.
In any case, Toyota's supposed electric supercar would theoretically go up against the likes of the Mercedes-Benz E-Cell, Audi e-tron and whatever BMW's Efficient Dynamics movement has cooking up. We should also point out that Toyota has indeed shown off a number of hybrid sportscar and electric vehicle concepts over the last few years, so such a project wouldn't be completely out of the blue.
[Source: Motor Trend]