Teardowns, Trophies And Angry Neighbors
Long-time residents of wealthy suburbs of New York are angered by the demolition of older homes to make way for new luxury houses whose size, they say, is not in keeping with their surroundings; trend has gathered momentum recently, and builders of luxury houses say selective razing of older homes represents an esthetic upgrading of the community; several towns are weighing strategies for scaling back the size of what some irritated neighbors call 'McMansions'; photos (M)