A feature request for Apple and Microsoft, and other OS developers. A way for an app to subscribe to a folder. I give you a callback and a folder. If a file is added, deleted, renamed or edited in the folder, call me with a path to the file. [Scripting News]
I would write a daemon that you would tell to monitor one or more folders with an action to take if anything changes in that folder. It would use unix-style configuration files (similar to crontab) with a command-line action. Since you can run an AppleScript from the command line using the ‘osascript’ command, this gives you the flexibility to do pretty much anything.