Several month ago (back in June, 2006), Ray Camden held an Advanced ColdFusion Coding Contest. The idea was an extensible tool to check ColdFusion code for potential issues.
This sounded pretty fun, so I created an entry (which took much longer than I anticipated). I am pretty happy with the results. Ray liked it as well.
CodeCop will check your code and report problems. The fun part is that, although it comes with some example rules, you can create any rules that you want right in the tool. You can also share packages of rules with others.
It will run in CF6 or better on any OS using any database supported by DataMgr (and if DataMgr doesn't support the database you want, you can add support for that database to DataMgr and then use CodeCop on it).
You can run it from within the ColdFusion Administrator (and thereby gain some functionality) or on its own.
Note that, as CodeCop allows you to read any code on your server and run ColdFusion code that you enter into the tool, it should never be placed where anyone can use it.
CodeCop is free and open source.
You can view screenshots and download CodeCop from RIAForge.
PS - Thanks for the great idea, Ray!