Maybe you did not exactly answer your own question, in regards to "when will the bottom fall out?" if that might be a fair characterization of your question - but aren't the best times to sell homes in the summer, so the end of this selling season comes in August/September, so might it not be fair to consider that a failure of the housing market (such as a bottom falling out) would be more likely to come after August/September rather than during the peak part of the yearly selling cycle?

Real estate fireworks in September or so?  Perhaps by August or September, individual owners are starting to realize that their houses are not moving, so they start to get desperate, in the event that they do not want to get stuck in their property for one more year.. so maybe the bottom starts to fall out in August rather than September or later?  

I'm just throwing out random ideas.  I don't really claim to know much of anything.