I like this idea, especially the flex fuel aspect. Something purpose designed to easily convert to run gasoline, natural gas, pure ethanol, you name it. Though

I like this idea, especially the flex fuel aspect. Something purpose designed to easily convert to run gasoline, natural gas, pure ethanol, you name it. Though it might have to have some sort of cycle to ensure you don't have 2 year old gas in your tank when you finally need to charge the batteries on the road.