Attached is a patch to make the plugin work in 0.12, as mentioned in #1040. It updates the code to match the recent API changes in Trac:MultiRepos, and also makes abbreviated SHA-1's work in Trac:TracLinks.
You'll need to make the 0.12 branch first (svn cp 0.11 0.12) before applying this. I wasn't sure if there was a way to include that in the patch itself. It seems that Git has pushed all the SVN knowledge out of my brain :)
Also, it currently only works if cached_repository is disabled; not sure why at the moment. But the rest of it seems to be working.