Late last year, the U.S. Navy posed a question to six of its favorite military shipbuilders: Would it be possible to build a warship, 200 to 400 feet long and displacing somewhere between 1,000 and 8,000 tons, armed with multiple .50 caliber machine guns, a 30 mm chain gun, and a helicopter, and capable of attacking a beachhead with a reinforced platoon of U.S. Marines — all for under $130 million?