Hugh Hefner is pushing 80, and he's sired four children - one of whom, Christie, runs Playboy Enterprises - but he sounds ready to spawn again. "Holly and I have talked about that," Hef told me yesterday as he held forth in his trademark red velvet smoking jacket in a bedroom at the Peninsula Hotel. "I wouldn't reject it out of hand. I certainly think it's possible." As for grownups David and Christie, from Hef's first marriage, and teenagers Marston and Cooper, from his second, they won't be consulted. "It's not a committee decision," Hef said. Holly is 25-year-old Holly...