Automated database migration from test to production

I'm working to achieve a test server + production server setup with Drupal. With code, it's easy. Just make the changes in test, then copy to production when they're ready (via a Subversion repository for extra credit).

However, database changes are problematic, and just about any development that involves clicking the Administration menu consists of database changes. The best practice guidelines on drupal.org and other sources suggest either (1) keeping notes on all activity in order to repeat the exact same sequence again on prod, or (2) copying the whole prod database to test, making all the changes, then copying it back. The former technique is time-consuming and error-prone. The latter technique loses any comments, posts, user registrations, and other changes made in the interim. (Unless the site is brought down during the changes--but a major purpose of trying changes out on the test server in the first place is to keep them from bringing down the prod server.)

Has anyone thought about making a script that copies only the configuration-related tables of the site to production, while leaving the content alone? Doing so would made configuration changes as easy to replicate as code. Certain actions would need to be performed twice, such as adding new CCK fields, because the database schema of the content changes. But many changes including variables and menu items should be transferred.

I've actually written a first cut at this, after categorizing a lot of tables. But so I know better what I'm getting into, does anyone else have experience with this kind of setup? Do any problems come to mind?