I'm not aware of any that are specifically for GLASS, but I am working on one with my coworker. It's very much geared toward our project and integrates a lot of different SCM type things together. It's probably awhile off for release, but we were thinking of throwing it out there with just a few of the smaller pieces. I don't think it is anything like what is currently out there, but just to give you an idea of what does exist that may be able to be easily ported:
http://code.google.com/p/smalltalklabsbrowserhttp://soek.goodies.st.s3.amazonaws.com/index.htmlhttp://groups.google.com/group/bibliocello (Dale's project, though strictly not direct documentation
http://magaloma.seasidehosting.st/You might want to talk to some of the authors of the above.