Mostly done. Right now it does the copying and updates the version.txt files. It doesn't do the Externals yet, but a coworker has argued that with Buildout we ought to go away from Externals.
Reinout von Rees has his own version that does a couple extra bits like eggifying. I like that very much, and may add a little more.
Alas, work is too busy right now to finish this before our next build. So I'm too busy to make my life easier. Ha ha.