Fisker Automotive has let slip that it plans to release a lower-cost plug-in hybrid vehicle, which will be “a step above” the upcoming Tesla Model S and Chevy Volt.

Speaking to Inside Line, Fisker spokesman Russell Datz said the new model would be significantly less expensive than the $87,900 2010 Fisker Karma luxury sedan (below).

“One of the future products we have is something that is significantly less than what will be on the market first,” said Datz.

“It may be a step above [the Chevrolet Volt and Tesla Motors Model S], but it’s hard to say right now.”

The new model is currently unnamed and Fisker says it won’t appear in concept or production form over the next 12 months. Little is known about the car, but considering the comparison  to the Volt and Model S, odds are it will be a mid-sized plug-in hybrid sedan.

Fisker also reports that orders for the Karma are flowing thick and fast. Approximately 1300 people have already slapped down a $5000 deposit for a Karma, with most of them residing in the green car-friendly state of California.

With Fisker’s dealer network expanding across the United States, that number is likely to climb even higher by the time the Karma enters full production this year.

[Inside Line]