in reply to DB Merge Replication

This is something that Sybase ASA combined with SQL Remote is really good at (which of course isn't really an answer that will be of any use to you...).

Building this sort of system in perl, and have it be reliable is likely to be a pretty serious project. I'd start with building a messaging system of some sort to push the data from the spokes to the hub. The main issue that I can see is making sure that updates are applied correctly, and that failures are detected (and retried if necessary.)