how to position windows just over the edge?

is there a way to position windows so the border is just over the edge of the workspace, such that when one moves the mouse so the pointer butts up against the edge, it's sitting on the scrollbar, not on the window's  border? 

I can't seem to do this from either the command line 
(using -geometry and setting the window at the edge 
or using negative geometries)
or from Sawfish's windows rules 

I hope there's a setting somewhere I can flip to do it. 

Thanks again to the creators and maintainers for this great tool. 

-- 
Sawfish ML