While the nation's lenders ran amok during the boom, Andy Beal hoarded his money. Now he's cleaning up--with scant help from Uncle Sam. BY BERNARD CONDON & NATHAN VARDI Standing outside the glass-domed headquarters of his Plano, Texas, bank in March, D. Andrew Beal presses a cellphone to his ear. He's discussing a deal to buy mortgage securities. In just a few minutes, the deal's done: His Beal Bank will buy $15 million of face value for $5 million. A few hours earlier he reviewed details on a $500 million loan his bank is making to a company heading into...