You’re worried that the law of gravity, as it applies to home prices, has been merely suspended, not repealed. Short of selling the attic (or a few outbuildings, if life has treated you very well), how can you hedge against a decline, if it ever comes?
The International Herald Tribune has a very good article on the upcoming launch of the housing index by the Chicago Merc. Actually, its more of a nuts and bolts article: Investing: New hedge on housing [IHT] 
Its going to be very interesting to see how whether this strategy compartmentalizes risk to the consumer. Here are some previous posts.