In my svn commit messages, I've long endeavoured to mention the issue it relates to (this predates the Subversion-Roundup integration).
Well, it turns out a single line addition to viewcvs makes all those issueXXX references in my commit messages into links to the tracker.
Just add the following to the htmlify function in viewcvs.py:
html = re.sub("(issue(\s*)(\d+))", '<a href="/tracker/leonardo/issue\\3">\\1</a>', html)where /tracker/leonardo/ is the path to your tracker.
And, of course, putting issueXXX or issue XXX in your commit messages is how Subversion-Roundup integration works too so you kill two birds with one stone!
--- James Tauber