Quick warning for everyone out there--performing an upgrade from OS X 10.7 (Lion) to 10.8 (Mountain Lion) will drop your Subversion setup. Expect to lose a lot from your /etc/apache2 folder, including your subversion settings.
I'm working on re-preparing my server, and at this time I haven't planned a strategy. I might rebuild a new Subversion server, or I may choose to use another source control engine--Mercurial and GIT both have their appeal. Details will follow once I have a strategy.
Update: I have found a resolution and posted it here. http://ubercode.bleakllc.com/2012/09/source-control-woes-and-resolutions.html