I don't know about Emplode, but jEmplode will allow you to drag-n-drop a directory and it will recurse through the folders and skip duplicates -- This is not _exactly_ what you want, but as long as your directories stay the same, it should roughly approximate it (i.e. any new songs would be added while the ones that are already there will be skipped). It will neither update modified songs nor will it delete songs that you have since deleted on your PC.

Mike