William Sofield is the designer equivalent of those extreme-sports adrenaline junkies who fly off mountain cliffs wearing nothing but a wingsuit, danger be damned. Over the past three decades, the AD100 Hall of Fame talent—whose client list includes titans of taste on the order of Tom Ford and Helen and Brice Marden—has happily embarked on his own perilous adventures, renovating a series of white elephants that mere mortals would not dare to touch.