I don't think it will be a train wreck. Here's why:
The mortgage lenders have overtightened, reducing their risk on new loans to even less than it ought to be. This will further supress the real estate market for maybe a year longer. As foreclosures rise, there will be a stopping point - not everyone is going to lose their homes, and they have almost peaked. A mini-peak may occur in about two years, but I think the worst of the foreclosures will occur before the end of 2007.
What will this do? Lower real estate prices. More affordability, and lower rates due to a slowing market and economy...along with lenders SLIGHTLY loosening subprime guidelines again - nothing like they were, but slightly moreso than now...and guess what? Sales pick up again.
Bottom line is, everything is cyclical. It's economics.