Rolls to Stop Building Convertibles: The British auto maker said it will finish production with 24 special-edition, turbo-charged Corniche S ragtops over the next four months. The firm has struggled in recent years with declining demand for its Rolls-Royces and Bentleys, caused partly by recession and partly by consumers’ preference for higher-performance cars. Rolls-Royce has slimmed down so it can be profitable on a production of just over 1,300 cars a year. “We’re a smaller company, and the cost of making each Corniche was increasing,” a spokesman said. “It required an inordinate amount of work for just two or three cars a week.” Rolls convertibles have had a long history among the famous.