A friend told me he saw something about an experimental truck that gave 650 HP, from an electric motor, powered by a small diesel engine, and it got 175 mpg.

Now he probably repeated half the story wrong, but any ideas at this point, are good ideas. ... And here's one from GM....
http://www.gm.com/explore/technology/news/2007/fuel_cells/volt_010707.jsp

As says Ted Turner about how ridiculous our current cars are, "We have a 200 pound man, getting into a 4,000 pound vehicle, to go get a 1/4 pound hamburger".

jeff