Audi has already conquered Le Mans using diesel-powered cars. So when it brought out the E-Tron electric sports car for a lap before the 2010 24-hour enduro, was it making some kind of veiled prediction? It could happen if the battery packs were easily interchangeable and could be recharged outside of the vehicle. This matte-black model was driven by German race ace Frank Biela. Although the E-Tron is still one of those halo vehicles to show off new tech, Audi is saying that a road-going version could be available in 2012.