Thanks for your patience, everyone.
We are now running MySQL 5.0 on the new hardware.
I've been spot checking customer sites at random and everything seems to be working. Please let me know if you run into any trouble.
One minor issue for people who access the database from outside of the cornerhost network: I have not updated the DNS entry for db.sabren.com, and don't intend to do so until I have apache working on the new boxes. If you need direct remote access to the server for some reason, you can use the IP address directly: 174.133.41.82
