Are any of the large construction companies publicly traded? How often do people finance their home with a loan from a bank? Which banks seem to be pushing loans to the unwashed masses the most? What about the DIY retailers and furniture retailers? (when property crashes, it takes those retailers with it). Short any of these companies.
Having said that, short-selling is (as you well know) extremely risky and very expensive: it requires you to bet on the amount of the drop and set a deadline. Something market-spanning like a property bubble is very very tough to predict (vs. an individual company that you can easily guess will miss their quarterly earnings), and even harder to find the contributing elements. Bubbles are all games of chicken. With property bubbles, you actually have governments and monetary policy and bond markets involved. Good luck.
