peep: Thanks for the link. Always good to look at other designs.
Flow: I'm actually hoping that shared users can be done with scripts and possible one or two small changes to ioFTPD itself. Using such a design it would be possible (in theory) to actually span glftpd and ioFTPD servers since the external sync tool I envision wouldn't be built into the servers themselves. I'm all for another scripter stepping up to the plate though
I've stopped day to day development on ioFTPD and started playing with learning a little C# since I think I want to build a new ioGUI in that language... That GUI could then serve as the sync tool as well since it would be able to connect to multiple servers and knows the users on each site so that's half the work right there!
We'll see how things go, and how much time I've got, but I've learned that getting lots of user input on this forum can take a while since some people check in rarely. I figured I better start the shared user discussion early in case someone has a feature or issue that would break the design I'm thinking of...