That may be possible in about three years if a retrofit kit invented by a former IBM engineer pans out in prototype testing. This is probably a more attainable (and affordable) set-up than the one reported a few weeks ago about that guy on Boston's South Shore converting Ford Explorers into electric vehicles for a mere $15k.

The hybrid concept developer, Charles Perry, is looking for doubling vehicle mileage by putting electric motors on each wheel, between the brake and hub. Batteries to drive the motors would be installed in the trunk, which prompts the question of impact on the car's weight and balance. Handling may also be affected because the unspring weight increases by adding the 10-15 hp motors on each wheel.

Perry says at 40 mph or less, a car equipped with his Plug-In Hybrid Retrofit Kit could go 30 miles on battery power alone. Target kit cost is $3,000 to $5,000—so you figure out the payback period for your car.

Read more about the kit and plans for its commercialization.