I've implemented a new rule-QA feature for testing out rules against the nightly-mass-check corpus -- it's described here:
http://wiki.apache.org/spamassassin/AutoMassChecks summary: we now have a set of scripts tied into BugZilla which will automatically take rules that have been uploaded, check them into SVN for our NightlyMassCheck runs, collate the results, and post them to the bug they came from. So, if you have any bugs open that contain rules that need a mass-check, take a look at that page, and (if necessary) tweak your bugs to use the right format, and remind us to tag them with a NEEDSMC tag ;) --j.