Good to know. There was another thread on here where some guy said "time to do bargain shopping" because he thought POS's would go up, and I sort of roasted him on it. What you are saying is an extension of that really - if you are going to invest in these conditions, there is still a lot of money to be made, but you have to be so careful in what you do. Investing in, or buying ANY house, is no longer a sure bet - so let him go bargain shopping anywhere, he'll lose his shirt.
While I don't know Caledon that well, I would never invest in it based on what you are saying. Forget the commute to the city aspect (which I agree with), it's the fact that its a 1 acre lot and an average price of $500k. No wonder they would be on the market for so long. The houses there are tailored to such a small and specific market of people.
The best investment houses will always be 25-year old houses, three bedrooms, two baths, working-class areas (both white and blue collar), in self-contained city-centres (i.e. have malls, good schools, civic facilities and the occasional MP for the hobbyist of course). There are two reasons. First, in a market frenzy these don't go up as much because they are not as glamourous as the newer developments, so when things crash, they don't have as far to go. Second, and more important, there is more likely to be a market for these houses in most any economy. I'm not saying that the market for this type of house will not soften, but it will not soften as much as those specialized one-acres in Caledon. Also, if purchased at the right time (at the lower-end of a correction) they would make very good rentals. I, however, would never be able to claim to know when to time purchases like this.
Ultimately what your analysis shows is that certain areas remain viable and others are in the toilet already. Moreover, when looking at TREB data, it is important to remember that they produce AVERAGES. I have already instructed my broker to focus on micro-areas, as opposed to entire sections of the market.