Florida-based BankUnited FSB last week became the latest option ARM lender to be dragged down by the severely distressed housing market and weakened U.S. economy. The company was shut down by the Office of Thrift Supervision. The Federal Deposit Insurance Corp. placed the failed bank and its $12.8 billion in assets as of May 2 into receivership. The FDIC said the agency and BankUnited will share...