Does anyone know of any Mac-compatible FTP software that can upload the same file to multiple hosts, in an automated fashion?
FileZilla should be able to do the task, it can connect to multiple sources and such, though I’m not sure how well it would sync files (never tried it). 
Thanks for the suggestion, but it’s not up to the task. What I’m looking for is FTP software where I tell it which websites to upload to, and it uploads the same set of files to all those websites automatically one after the other.
With FileZilla and other typical FTP software, I have to select a set of files to upload for one site, then select the same set of files to upload for the next site, and so on. If I have 100 sites and want to upload the same 10 files to each of them, automation would really help.
After trying pretty much every Mac FTP program there is, I’ve found none of them can do it. I ended up using SmartFTP running in a Windows XP VirtualBox. It has a ‘multi-upload’ feature that’s a little buggy in the current release but at least it works.
I use Transmit. If I define two sites – different remote connection, same local directory – I can just drag the files from that directory onto the Transmit icon and off they go to both servers.
Crunch, I use SmartFTP myself for all my uploading (Windows), I agree that it has stuff going for it no other client has, I guess you wanted one of those features!
Have you tried Fetch on Mac? It works just fine for me! So did Transmit! On Windows I use CuteFTP/Filezilla/FireFTP depending on the PC I am on and the task to achieve…