The housing market in the Detroit area was the first to go bust. In fact, there was a story on the radio a year into the slide about how a multi-million dollar mansion in Detroit went for 135,000 in a public trust auction.
Interesting move. I'm sure there isn't a lot of demand for a "used-stadium" though. It'll cost quite a bit to demolish and clean it up, and then more to build on it, so the bargain is relative.