Add electric car company Tesla Motors to the list of companies building plug-in hybrids. The Silicon Valley company will produce a second model of the Whitestar EV late next year that also has a small gas motor to recharge the batteries. It will be similar to the Chevrolet Volt, which labels itself as an "all electric vehicle."

Tesla is smart for hedging its bets with a plug-in to go along with its EVs. There will be ample demand for both vehicles in the coming years, and many folks might prefer the extended range of a PHEV.

I consider both of these plug-in hybrids because like the models being developed by Toyota, they run on batteries until they need refueling by gasoline. Sure, the gas motor doesn't cause locomotion but instead charges the batteries, but to most consumers that's just a detail. If the electric drive system fails on the Tesla or Volt, you ain't moving, but with the other plug-ins, you might still be able to go using just the gas.

So in the running for the title of first mass-produced plug-in hybrids we have:

GM Ford Toyota Tesla Fisker Visionary Vehicles AFS Trinity BYD Auto (China)

I'm still betting on Toyota to be the first out of the gate, but Tesla could be a close second.