I've previously talked about my desire to use subversion as a persistence layer.
I've now started to work out how to use the Python bindings that Subversion comes with—mostly through studying the source code of ViewVC (formerly ViewCVS)—and it looks like it definitely meets my needs.
I've written up my notes so far as a page for others wanting to use the Python binding. Hopefully it's useful to other people:
It's a work in progress and I'll add more as I discover and use it.