Volkswagen has designed it, it's called the XL1:
The XL1 represents the car as blue-ribbon science fair project. But unlike other megacars, which are built to maximize speed and power, this one, more than ten years and upward of a billion dollars in the designing, contains not one centimeter of wasted space or poundage. The engineers eliminated power steering because it would have added 10 kilograms. For maximum lightness, the core of its body and chassis is comprised of a one-piece molded carbon-fiber monocoque. The magnesium wheels get wrapped in custom-light Michelin rubber. The windows lower with hand cranks. There’s no radio — the sound system wraps through the Garmin GPS — and no place to plug in your smartphone, because Bluetooth is lighter.