This is just amazing, from the Frankfurt Auto Show, and scheduled for mass product in 2013:
Called the L1 and feature a carbon-fiber body wrapped around a 0.8-liter twin-cylinder turbodiesel engine developing 36 horsepower and matched to a 7-speed dual-clutch DSG and a 14-horsepower E-motor hybrid electric drive system. With a curb weight of just 1,100 pounds and a super-slippery aerodynamic body thanks to its tandem seating layout, the L1 is claimed to return a fuel economy of 157.8 mpg (1.49L/100km)—we think this is low enough to warrant the L1 or ‘1-Liter’ name.
The 800 cubic centimeter turbodiesel engine in the L1 is essentially half of the 1.6-liter unit found in the Golf and Polo BlueMotion vehicles, meaning it is a series-engine-derived mill. Performance isn’t as terrible as you might expect from a hyper-frugal hybrid, either: top speed is 100 mph and it can reach 62 mph in just 14.3 seconds—not so far behind some standard cars on the road today.