Oh, and don't forget that mortgage rates don't have to go up to have the bubble POP. In Japan, rates stayed low, but creditors stopped writing new loans. A credit crunch is almost as bad as high rates - if buyers can't get financing, sellers can't sell the day the house goes on the market. Mortgage lenders in this coutnry will tighten if they start to fear the rate of defaults or the lenders can't find money to lend.
RE: timing the top: it is tough. The current outflows of capital in the market are going into CDs, savings accounts, and money funds. Banks and money managers are looking about for places to put all that money and i'll bet that lending money for mortgages looks pretty good. But once the outflows from the market taper off or people do something with the money they have parked in cash, mortgage lending will tighten. Scarier is the issue of the dollar and foreign capital. If dollar drops too much, foriegners will want to pull out of money-losing investments in the U.S., and inflation will kick-up due to price increases in imported goods. Capital flight and inflation will both drive up interest rates AND leave little money to lend.
-Traden4Alpha