Using the Pebble Beach Concours d’Elegance as a backdrop, General Motors’ luxury division unveiled a new concept coupe that foreshadows an all-new rear-drive flagship line that could appear within two years. The Cadillac Elmiraj is a hardtop coupe powered by a 500 hp twin-turbo 4.5-liter V-8 driving the rear wheels. While Cadillac has scotched rumors that it would build a super-premium sedan to rival cars like the Bentley Flying Spur and Rolls-Royce Phantom, executives have said that they are looking at a rear…