Have a look at the accompanying photo:waitasec: Were it another discarded mattress or a hubcap on the lam, people wouldn't raise an eyebrow at the castoff left in a ditch along U.S. 301. But, as coffee stand owner Georgenna Malone points out, "It's kind of hard to miss." It's a house. Not a whole house, but the three-bedroom, two-bath second floor of one - freshly painted sea foam green - resting on a set of rusted beams and wheels just below the Interstate 75 overpass. For about a month, the mystery has puzzled people along this rustic stretch of highway outside Temple Terrace. "We've been trying to figure out what the hell is going on out there," said Lisa Power, records manager for the Temple Terrace Police Department. There's no "For Sale" sign. No moving permit. Nothing to trace the house back to its owner.