Fresh from freshmeat:
http://www.ditrack.org/
What is DITrack? DITrack is a free, open source, lightweight, distributed issue (bug, defect, ticket) tracking system using a Subversion repository instead of a backend database. It is written in Python and runs in UNIX environment (*BSD, Linux, MacOS X). The project is inspired by the idea of Subissue issue tracking system. However, while Subissue aims in merely replacing the traditional database storage with Subversion repository, DITrack is a major rethought of the issue tracking system paradigm. The main difference is that instead of sticking to the centralized model (one database, one web interface, one mail integration machinery), DITrack treats underlying Subversion storage as a versioned distributed file system which enables benefits of truly distributed operation mode.