The CIM Group revealed a rendering on Wednesday of a new 1,300 foot tower near Central Park that would be the tallest residential building in New York City, joining a half dozen new developments that will break the 1,000 foot height in coming years. Although financing woes and market uncertainties mean that construction has begun on only a few of the projects, all have gained land use approvals and, if completed, will substantially alter the skyline. And while more radical designs exist in other parts of the world, these cloudbusters are rising on some of the most expensive parcels on earth, and profits are always a consideration.