FYI, There have been several iterations of the Shopsmith Overarm Pin Router. It began life as the Bryco/Shopsmith Pin-Router (505825) with no guard, no dust collection, a simple plywood table and the router motor was held in place with two hose clamps. (See photo #1 above) This version of the Shopsmith Router Arm was shown in the Mar/Apr 1980 issue of Hands On! Magazine for $495 w/o router motor, $595 with 1 1/2hp Milwaukee router motor.
The old units will pop-up on eBay at a rate of one-two per month, and they tend to sell in the $200-500 range, depending on whether there are routers or bits included, the overall condition, and the copyrighting skills of the seller. I’m not kidding about this last point. I've seen pristine SS tools go for next to nothing because the seller didn't bother to talk about the tool. In other cases I've seen worn-out tools sell above the current retail because the seller was a wordsmith! (The Ron Popeil fan in me has to respect that on some level.)
The video below shows a Shopsmith Router Arm being used to make parts for a cheese fountain.