It turns out that caffeine deprivation is not a good thing. Following copious quantities of Jamaican Blue Mountain bean, I successfully mounted Trolius (my new Samba server) on the network as a master browser. It worked, and I have no idea what I did differently. This is why I usually write things down as I do them.
The next step is to relocate this machine to a remove location, connect to the network at the office using OpenVPN, and start experimenting with rdiff-backup. Hopefully I'll have some time to do that over the weekend.
It's good to be back to coffee. I don't think I'll try giving it up again...