Worked my way through a bit more of my system, and found another thing that’s not very happy with Leopard. Turns out that the MySQL Community Server (the free one you can download from mysql.com) really doesn’t work on Leopard, and it seems that it’s primarily the Preference Pane, startup item, and socket locations that need tweaking. Actually, people seem to be saying you should just ditch the preference pane and the startup item entirely. Apparently during the upgrade my data disappeared, too, which is somewhat entertaining. It was all testing data, and I can easily pull it from the production sources again (or even boot my backup drive and dump it from there.)
At this point, I’m probably going to just install the macports version of mysql (and postgresql) and use that. The Mysql.com version was nice because it included the StartupItem and a nice Preference Pane to control the service, but that was, really, its only benefit.
For an idea, simply searching on Google for “mysql leopard” will give you a number of useful and relevant items.