Okay, after my good friend Lonnie showed me how I could hide the app, here is the version that works as originally intended: ActiveWindowStatus.app. It looks as though Lonnie wrote a more elaborate version of the same idea. I guess I'm not reinventing the wheel...
Just untar it and drop it into your Library/Scripts directory. Then you can get it to start up automatically when you log in using the Accounts section of System Preferences and it'll happily run in the background like a good little daemon should :)