Okay, so the Segway hasn't lit anyone's imagination on fire, but Dean Kamen's Luke Arm promises great things on the prosthetic front. Now his DEKA Revolt may be pointing to an interesting transportation option, a hybrid car with a Stirling engine.A Stirling engine works with any external energy source heating the controlled volume gasses contained in the engine cylinder. As the gas expands from heat, it forces the pistons to move. Lots of math and physics later, you get mechanical energy at the crank. Traditionally the Stirling engine is used with waste heat for low speed, high power stationary applications, but Kamen's team has folded it into a hybridized Th!nk City as the on-board generator for the electric drive system. Obviously the details on the DEKA Revolt are still murky, this is Dean Kamen we're talking about here. But the idea of a Stirling engine hybrid is intriguing. Because of its design Stirling's are inherently super efficient when talking about piston engines. Add to it the super-flexibility of the fuel source for the heat and you've got an equation which adds up to a great idea. Now, whether or not this thing actually comes to fruition or not is a whole different matter. [DEKA, FoxNews]