glyph> *can* always do that, and some other Twisted devs watch glyph> python-dev a bit more closely than I do, but the point is that glyph> the amount of effort required to do this is prohibitive for the glyph> average Python hacker, whereas the time to set up an individual glyph> buildbot might not be.)
If you're concerned about noticing when a new release train is pulling out of the station I think it would be sufficient to subscribe to the low-volume python-announce mailing list. You will see announcements about alphas and betas there. Even lower volume would be a subscription to the RSS feed of Python announcements on the python.org front page (scroll to the bottom).
The buildbot idea sounds excellent.