Builders are banking on Miami's magic in a big way. Somehow in the next two to four years -- poof! -- the downtown area, from Brickell through the newly christened Biscayne Boulevard Corridor, will fill with some 40,000 new residents eager to shell out a quarter-million to a million bucks to live in so-called lofts in chic neighborhoods. For now, many of those neighborhoods are largely imaginary, hopeful names scribbled in developers' dreams: the Performing Arts District, the Cultural Arts District, the Florida East Corridor. The names of the new so-called loft projects are no less whimsical: Aria, Quantum, Platinum, Star, Mist, Blue, Sky, Ice. But who knows? Sometimes developers' dreams do come true. Maybe in five years or so Miami will be transformed into Manhattan south, with well-heeled culture vultures perched in high-priced nests overlooking Biscayne Bay. On the other hand, maybe there aren't quite so many gritty culture hounds with deep pockets ready to move into little skyboxes in America's Poorest City. Maybe then the prices will come down and families from the shrinking middle class will have a chance to move into condos with "endless views of Biscayne Bay." It's possible not even the middle class will buy into the developers' fantasy, and the buildings will stand empty, sky-scraping testaments to another crazy Magic City scheme. That could be cool, too. Imagine mile upon mile of empty towers. A wild squatters' underworld. A sultry Blade Runner. Instead of the art scene driving development, once again we'll have urban decay driving the art scene.