WASHINGTON — A few weeks before the Republican primary in Florida in January, the billionaire owner of the NFL's Miami Dolphins hosted a fundraiser for Mitt Romney at his oceanfront home in Palm Beach. The average voter wouldn't know about the event at the home of Stephen Ross because Romney's campaign doesn't follow the practice of other major presidential candidates who have willingly identified big-money fundraisers and the amounts they collect. A review by The Associated Press of campaign records and other documents reveals hints about the vast national network of business leaders bringing in millions to elect Romney. The...