If you've ever dreamed of living in an art gallery, a new, New York City building is offering the next best thing.   Tucked among the former tenements of the Lower East Side, the Switch Building places four one-level, full-floor apartments and a duplex penthouse above the new, non-profit Switch Gallery – giving a few lucky art lovers the chance to live their dream.  The gallery is just a part of the burgeoning art scene that makes the area, once famed for its Jewish immigrant population and tenement housing, one of the Big Apple's hottest new 'hoods.