True, but the overall value proposition diminishes rather quickly as the price goes up. It's only a few hundred dollars a year saving on gas between the Elio and a Versa (12k miles/yr and $2.75/gal). The disadvantage of only being a two passenger vehicle (or one passenger + any meaningful cargo) needs to be made up somehow and I don't think the better mileage will do it on its own.
Way more pluck for the buck....