Unicorp National Developments Inc. of Orlando is planning to build Dellagio, a $100 million, 118- unit, upscale residential and retail complex at the corner of Sand Lake Road and Della Drive. Principles Chuck Whittall, a resident of Isle of Osprey at Dr. Phillips, and Lee J. Maher of South Bay Villas expect to break ground early next year and complete the Mediterranean-themed project within 18 months.