The Peterson Cos. has proposed another major new development for its National Harbor mixed-use project in Prince George’s County, Md. The 16-story building would be located adjacent to the million-square-foot MGM National Harbor casino-resort that is expected to open in the fourth quarter of 2016. The scheme for the new project calls for a 1.2 million sqf mixed use facility containing a 500-room hotel (200 more rooms than the 308-room hotel planned by MGM), 702 apartments, 189 timeshare rentals, 22,000 square feet of retail, 972 restaurant seats and 22,000 square feet of entertainment related spaces. The plans also call for an enclosed walkway to MGM, a 2,070-space parking garage and an outdoor pedestrian plaza.