As concerns mount over soaring fuel prices and the United States’ dependence on foreign oil, ethanol is emerging as a controversial balm for the nation’s growing energy problem. Politicians and automakers say the corn-based biofuel can reduce demand for gasoline.

In the highly competitive world of fast cars, sometimes the hottest picture is a snapshot showing little but the wheels. But auto enthusiasts are so anxious to see what a new model will look like that websites and magazines will pay thousands of dollars for pictures of prototypes camouflaged with patches of fabric.