Hi,
It's a darn shame there can't be a private buildbot running a public OS beta, to get an earlier jump on new OS support, not to mention a field in the tickets explicitly for port version, so that the buildbots could on build failure automatically check for, and if not found, submit tickets for build failures, making them a more useful part of proactively fixing build issues, perhaps sometimes before any mere mortal even noticed. :-)
There is no *technical* reason why that could not be done. Once the public beta OS is available in theory a buildbot could be set up running it. The issue is more the NDA you effectively sign when you agree to running the beta, that prevents you from (too) publicly discussing issues related to the beta OS. What you describe above would be fairly public....
There is also the fact early betas often have issues that disappear before release. I was running the early betas, either in a VM or from a second external drive, from early on and indeed there where some issues I found at first that causes quite some problems at the time, that Apple fixed in subsequent betas. So worrying too much about things too soon before the final release can also be counter productive.
I know a number of people where running the betas and we did privately discuss a number of things. For instance the 32 bit issue was present in the first Xcode betas. It wouldn't though harm to have more people running the beta and testing things. This is quite easy to do and you do not have to over-write your primary system to do it, as either a VM or a second external bootable drive both work quite well for this sort of testing.
Chris
