GMAC’s highly profitable mortgage subsidiary, Residential Capital Corp., is quietly positioning itself for life after separation from its ailing parent, General Motors. ResCap includes both Residential Funding Corp., a leading private MBS conduit, and GMAC Residential Holding Corp., a top residen-tial mortgage banker. Cerberus Capital Management, a hedge fund, is currently set to close on a $14 billion deal to ac-quire GMAC by the fourth quarter of 2006. Once the sale is completed, ResCap will dispose of its in-terests in GMAC Bank...