Couldn’t find this in my archives, so putting it there now.
Tony MacDonell @ Teknision built this JSAPI + XUL + Window SWF extension that opens up the source folder of the FLA your currently working on. Don’t know if it works on Mac, but on windows, it only works if you don’t have IE open.
Anyway, I use it all the time. …course, if Chafic could put this feature in his Flash Tray Tools… but I’ve already asked for a feature.