I\'ve used Trac/Subversion before and really like the integration. My current project is using Mercurial for distributed development and it\'d be nice to be able to track issues
I recently developed a Trac plugin that integrates some Mercurial functionality that TracMercurial Plugin doesn't support yet, it's called TracMercurialChangesetPlugin. It allows you to search in your changesets, to have the cache synced, to view a changelog in your related tickets...
You can read about it at http://tumblr.com/x8tg5xbsh