Isn't the camera a good enough handle for you?  It looks to me like you'd have cross your arms to pan via your handle and fire the shutter at the same time...

I made some modifications to the Wimberley head to allow   panning  for birds in flight.

Please see my Sherpa page and go to page 2 http://home.earthlink.net/~mr1634/
For information and pictures.

Thanks, Mike

Looks like he has a remote release on the handle in one of the pics.

I find grabbing the camera grip and swinging to be superior. I could see the point of the rig if you were able to view the scene from a distance (like a couple of feet) using a large viewfinder (ala studio video cameras), but don't see the usefulness when you have to have your eye mashed up to the camera anyway.

Perhaps he will explain the why.