Change management solution for BP-based site?

I administer a social networking site that runs on WP, BP, and WP Multisite. Currently I have two servers: development and production, but I plan to move to three: development, staging, and production. Is there some piece of software out there that will allow me to push changes from development to staging, and staging to production, with a single command? Bonus points if it’s web based. Also, since it’s a social networking site, I can’t overwrite any content that the users have generated.

There is no settled solution for change management in a WordPress environment.

I recently wrote about one approach, that might be helpful.

@scribu then brought our attention to this new ‘Ramp’ offering for content staging. which might be of interest, depending on your use case.

@MikeSchinkel has his own potential solution which doesn’t attempt to preserve of user-generated content, at least initially, but is definitely worth checking out..