On the campaign trail, Barack Obama promised to get a million plug-in hybrid cars on the road by 2015. His own new presidential limousine will be far from green, however. The Obamobile being prepared for the president-elect is said to be a monster gas-guzzler made by General Motors, the troubled car giant. It will look like a black Cadillac but is built like a tank. A spy photographer who tracks down future car models for magazines snatched pictures of the heavily disguised first-car-in-waiting when it was being road-tested last summer. The armour-plated car, which has a raised roof, windows up...