I used to use sshfs but it wasn't stable enough. 

I would also love to have the functionality to work locally on a remote working copy. Having said that I also work with SmartGit (Linux version) running on a headless server (even on an HPC compute node) with the SmartGit windows simply on my laptop (Mac using the Quartz  X11  server, but I'm sure one could get it to work with a Windows X11 server). It is of course slightly laggy but works well enough for the more complicated things (for simple things I use the command line). 

I was really surprised that you can't see the contents of an annotated tag; should be easy enough to add, right?