Yes, folks, we're well aware that the Froyo ROM we're all running on our Nexus Ones isn't a final build. We said as much on Monday, and it was confirmed by Google just a couple of hours later and has been reiterated several times since.
Think it through: The Froyo update first started showing up on a few devices -- journalists no less -- and these were devices that originally were distributed by Google. So the Goog knew the IMEIs -- a unique identifier of the phone -- and started pushing out early updates. It was a targeted distribution.
When an over-the-air update is pushed, it actually just tells your phone "Go to this Internet address to download the update." From that point, it's just a matter of finding the download location (which takes about 30 seconds if you know how), and that's the ball game. The rest of us now have this early version of Froyo.
Rest assured, we'll see a more final build soon, and hopefully we'll have the source code released before then so that our favorite chefs can get to cooking. As for when a specific phone will get a Froyo update, well, we don't know. And it's really unlikely anybody else does at this point either. So be careful in reading those random posts from customer-service bots or some guy in a store. We thought we'd taught you better than that. :)