OK guys, Al Ladd, who makes the Proteus Power Feeder, saw this thread and tried to join and respond, but he has been unable to do, due to some kind of registration error (I have no idea).
He asked me to post this to the thread, as a FYI... so here goes...
"Great to see my power feeder being discussed here! I think Shopsmiths could be a fantastic use for my power feeder, and they fall into the category of machines too small and light to use a conventional feeder on, probably even the Comatic "baby feeder". I think my feeder would mount onto a 510 or 520 fence with no alteration of the Shopsmith, and it would also clamp into the t slot miter gauge slot with an easily made plywood holder. See attached photos.
I want to address a couple of the comments people have had. As the attached photo shows, my feeder is about as bulky as a "baby feeder". It weighs about 13 pounds without the drill attached, which adds 3-4 pounds. The Baby feeder weighs 27 pounds, an extra 3 with the steel plate shown in the photo which helps in mounting. Visual access to the saw blade is not something one usually gets when using any stock feeder. Best practice is to to set up with the stock feeder not yet in place, and then attach the feeder. So fast installation and removal is important. This is a big advantage for my feeder, which removes and installs as fast as Jessem guides.
Speaking of which,--I love Jessem guides! And my feeder plays well with them. It can mount in the same track as they do, and on a full sized table saw, and maybe with a Shopsmith, you can put a Jessem guide in front of the feeder, and both power feeder rolls behind the blade, and the stock will be handled very safely all the way through the cut, perhaps even leaving the riving knife in place. If the riving knife needs to be removed, I recommend an insert with a splitter.
All this said, I think the best use of my feeder for most woodworkers is in resawing on the band saw, and the second best is a router table. But of course Shopsmith owners are special, and I think my feeder can be a great addition to safely working in several modes on a Shopsmith.
I'm willing to sell any kit at half price to a Shopsmith owner who will report back here, and refund the balance if they post a video of their installation to Youtube. Contact me at firstname.lastname@example.org