[RP] keyboardless synergy screen switching?

[Brian Edmonds]

My current setup at work has a linux desktop machine and a linux
laptop, both running ratpoison, and joined by synergy so I can just
use the desktop's keyboard (and mouse where necessary).  I'd really
like to find a way to move between the desktop screen and the laptop
screen without grabbing the mouse, and it should be really easy: just
move the mouse down a distance equal to the (desktop) screen height. 
And then the equivalent thing back the other way.

Unfortunately I can't find anything to easily control the mouse this
way.  Ideally I'd like to be able to bind a ratpoison keystroke to
some internal or external command that will move the mouse by a preset
amount.  Any ideas or suggestions?

Brian.