[Al Skierkiewicz]

Anthony,
You can manufacture this out of stock parts from almost any source. Check with Small Parts, Inc. though. I think your dimensions on the focus ring are off by a factor of 10 though, it looks more like 28 cm in circumference. The part is assembled from a right angle drive, (black knob is on the input shaft and the brass pulley is on the output shaft) two brass pulleys, belt and a mating gear for the larger gear. The part you show has a custom part to hold the right angle drive and the upper shaft (likely holding a bearing in the upper part of the housing.) The thumb screw on the bottom allows side adjustment to mate with the focus gear. You can buy the base plate from a camera store like B & H in New York and add you own arangement to hold it all in place. The rods are not a necessity but likely are used on other camera attachments from the same manufacturer. You might want to check with the manufacturer for a "studio kit" which might be cheaper and provide a remote focus knob that would be easier to use than this one.
A word of caution, messing with the lens of any camera is risky business. If you permanently distort the focus ring, or accidently over drive it, the cost for repairs is astronomical compared to the cost of the camera since this is not a removeable lens. It is possible to cause the lens to become a "fixed focus" if the ring or internal parts are damaged.