After a few other roll adjustment experiments, I decided to bite the bullet and go for active stabilization, so I added a GS-1 for roll stabilization. (which BTW, is a very nice piece of kit, and was delivered very quickly)
You can find the results here: http://www.youtube.com/watch?v=LBCaXqZEaTw
Pitch and yaw are adjusted using a feeler as I described here on the "First Person" camera rig thread a few years ago (which I'm not going to link to because google seems to think it's got some malware links right now)
The video was been post processed through VirtualDub and Deshaker as you can see through movement of the black the border.
10 points if you can guess where this is taken!