If you are still interested in making one of these, I will be offering kits for sale on ebay as soon as I get them finnished. My test/demo model can be seen on youtube: http://www.youtube.com/watch?v=oxHGpqMFElI
That's the link I have too ! Enough there to make one I think.
The one example I've seen WAS made of wood, apart from the prod, so start drawing ! Steve