I guess I can't see the forest through your trees. What's so bad about having rsync run on the empeg as the client? Sounds like someone already solved 90% of the problem, and you're tossing that aside and inventing a new problem, but in the opposite direction. What needs are not met by having rsync do a "pull" from your music server instead of having the music server "push" files to rsyncd on the empeg?