The first half of the year produced few surprises on the subprime production front: mortgage brokers continued to provide most of the muscle for the sector while lenders focused most of their efforts on borrowers at the upper end of the credit scale. According to a new analysis by Inside B&C Lending, mortgage brokers accounted for 56.3 percent of the estimated $298.06 billion in new subprimeloans produced through the end of June – about…