Just chiming in to say that banking on a RE crash in Portland is a very risky proposition. The fact is that Portland is most likely the newest member of the Bay Area/Seattle/Vancouver triumvirate. Prices aren't going up because people are over-leveraging themselves, prices are going up because demand is shooting through the roof. People are trading their Seattle and San Francisco houses for an upgrade in trendy Portland of the NW, a city with all the charms of the other large western cities, but without many of the annoyances of its larger neighbors. If anything, I wouldn't be surprised to see Portland's market continue upwards. Hell, even secondary western cities such as Bellevue, Tacoma, Eugene, Salem, Corvallis, Bend/Redmond, Ashland, Redding, Sacramento, Santa Rosa, etc are going through their own mini-booms.
I could see the market flattening out... I would be very surprised to see it actually drop. How did the 2008 crash affect San Francisco and Seattle? How quickly did they recover? Now the markets their are above where they were during the previous bubble and still climbing. Unsustainable? It's hard to say, but given the economic growth in the tech sector, I wouldn't bet on it.