The Prius is way nifty. An idea I've been tinkering with and gathering components for is a hybrid drivetrain for SUV's. Got the idea about 10 years ago for using ethanol to power a turbine-electric system. Nice thing is, ethanol is domestically produced and clean burning. You can even make it yourself! The system is compact enough to fit under the hood, can be digitally controlled and produces a tremendous amount of power for its size and weight.

Pretty much a variation on a theme, but would suit vehicles like the VX and have sportscar-like performance.