Not entirely a new idea!

When Huey P. Long was the governor of Louisiana, he was a big football fan and wanted the state to build a new stadium for LSU, but they wouldn't give him the money. He found out that there had been money set aside for new dorms, though, so he built a bunch of new dorms in the shape of a football stadium. LSU students lived in Tiger Stadium until the early 80s.

Another example I can think of is that, for a time when the As were still attempting to get the city of Oakland to help subsidize their new ballpark, they were proposing that their new stadium at Howard Terminal (a port) would have housing built into the stadium. Obviously they are moving to Las Vegas, though, so that's dead.

And then of course you have all the other old ballparks that got torn down and replaced with housing. There's a huge public housing complex on the site of where Ebbets Field (former home of the Brooklyn Dodgers) used to be. Same with the Polo Grounds, former home of the Yankees.