There are a few potential options on the table, it's been long wished for that Uni would buy out Dr Phillips HS and utilize that land since its so close however knowing the current state of Central Florida schools and the politics involved the chances of that happening seem pretty small.
Then you have the collection of commercial properties currently sitting across Major Blvd most of which probably could be bought out giving them a decent chunk of land to work with, I would think this would be the easiest option. However Disneyhead over at OU hinted earlier today that they may be looking to expand across I-4 into the Wet and Wild land and further back into the old Lockheed complex which they owned at one point. That could net the best returns as it would tie them into the Orlando Convention area which has the largest amount of hotel rooms in the city outside of Disney World.