MySQL 5.1.7 introduces a new RENAME DATABASE command. Today, I've updated my BitKeeper MySQL 5.1 version, so I had the opportunity to already test this command. I found two bugs, which will definitely be in 5.1.7, as the development tree has already switched to 5.1.8:
Bug 17564: the RENAME DATABASE command doesn't change the privileges, so privileges might be lost, when the database name is changed.
Bug 17565: all events that were stored in the database will be lost after the database is renamed.