I currently use Synergy to allow my mouse and keyboard to automatically float between 2 machines and it works great. What would be even better though would be a way to make a desktop on the slave machine that is really an extension of the desktop on the master machine, making it look like it was just an extension of that machines desktop.

This way I could have all of my monitors creating a huge desktop (for when I'm doing lots of documentation work). I currently use a two head card on my main machine and thats great, but having my slave machine become a desktop extension giving me that third monitor would be tremendous advantage.

I don't want to run stuff on the slave machine, just give myself a desktop extension over the network for those times when I need it. Of course sometimes being able to run stuff there and switch back to the desktop extension would be nice.

Anyway know how to do this?