I have a desire to build my own router pantograph for cutting wood gear clock parts. I want to use the pantograph to increase accuracy without resorting to a super expensive CNC router. I have used a pin router and actually like the cut quality better than the results from my homebrew CNC machine with a bit too much flex.
It seems like a pantograph would allow me to cut a large scale template and any errors would be reduced by the scale factor. So far the design only exists in my head.