Thai-Swedish Assembly (TSA) is most likely to win the temporary contract to paint body parts for the new 7-Series when BMW starts building the luxury saloon at its Rayong plant next year, sources have told The Bangkok Post newspaper.   The TSA factory currently builds Volvo and Land Rover vehicles. Other plants being considered by BMW for the contract include General Motors, Thonburi Automotive Assembly Plant and YMC Assembly, according to the report.