I picked up the Adafruit USB microscope (http://www.adafruit.com/products/636 ) and the arm on it was pretty terrible. This replacement clamps onto the 7/16" diameter rod of my Panavise for easy inspection of boards. It is 5" long which gives it a lot of reach and is held together by 2 1/4-20 screws and nuts. There are hex slots in the bottom for nuts and I plan on making some knobs for the hex screws for adjustment. The plastic provides solid clamping friction but I can move the camera without undoing the screws.

Just print it out and assemble with 2 screws and nuts.