Life at the Top Is About to Rise 175 Feet or So
Scott Toberman is building what should be world's tallest building in Chicago, and the 52d through 92d floors will be apartments, the uppermost one 1,177 feet above ground; 2,000-foot-tall tower, Seven Dearborn Street, is being designed by Skidmore, Owings & Merrill; it will also have office, parking and television broadcasting equipment, a fact that might allow Trump World Tower in New York, whose highest apartment will be only 817 feet above ground, to remain 'the world's tallest residential tower' because it will be all residential; Richard F Tomlinson II, managing partner of project, describes efforts to minimize sway, noise and chances of a power failure; photos; drawings (M)