Toyota’s 1/X weighs in at a mere 926 lbs and is made primarily from bio-plastics. The fuel efficiency is twice that of the Prius, due to the fact that it weighs much less and only carries 4 gallons of fuel. That four gallons will drive over 600 miles.
It is currently in the concept stage, but with the current line of hybrid vehicles garnering a wait list for purchase one can only assume that such a vehicle will gain a fanbase rather quickly.
(Source: EcoGeek)