Florida's beaches will be the draw this weekend as the National Association for the Advancement of Colored People hosts a swanky retreat at a Destin resort to help boost its membership among affluent 30- to 40-year-olds. With registration starting at $325, a golf tourney on Sunday and massages i n between, the National Leadership 500 Summit that started Thursday and runs through Sunda y likely will be an exclusive gathering of the country's young black elite. And that's exactly what the NAACP is hoping for. "I have issued a call to my peer group," said Roslyn Brock, 39, summit creator...