Joanne Kaufman and Katherine Marks

Faith Popcorn, thought leader, trend-spotter and flamboyant futurist, never saw townhouse ownership in her own future. In the early 1990s, Ms. Popcorn (originally Plotkin) was living in a small studio apartment with a Murphy bed, a rental turned co-op. She felt wonderfully comfortable there — until a friend from California, who “had this gorgeous place