Yes, where we feel it's the best solution (our standard key-value store is voldemort). SQL changes are peer reviewed and applied with a set of scripts we have to make the process easier. This isn't integrated into the deployment service yet, but it's something we've talked about.

http://news.ycombinator.com/item?id=411282 has a good description of something that's very similar to our SQL rollout policy:

"only add columns to tables and new tables, never to remove anything, so the database can be upgraded hot, and the old code can continue to run on it, only the new code will see any new columns/tables."

and

"Once you are sure you are never going to roll back to the old code you can wipe out the old columns."

This comment (and its author) http://news.ycombinator.com/item?id=411358 were formative in my views of service deployment.