[CarveOne]

I'm thinking that a round neoprene sanding disk with integral 1/4" shank for hand drills might work. If the disk can use hook and loop backed sanding disks with the holes in it the loading up problem may not be so bad. An air tool mounted on the z axis may be too noisy but an ac powered hand drill could work. For continuous duty production sanding a better motor solution is needed,

CarveOne