4. Rolls-Royce Phantom IV – Built for Royalty… Literally
The Rolls-Royce Phantom IV was an exclusive model produced between 1950 and 1956, with only 18 units ever made. (en.wikipedia.org) This rarity was due to its production being limited to royalty and heads of state. (topspeed.com) The first unit was commissioned by Prince Philip, Duke of Edinburgh, and delivered in July 1950. (press.bmwgroup.com) The model featured a straight-8 engine and was the only Rolls-Royce to do so. (superstock.com)