HP-28S preservation

[Dave Britten]

I faintly remember seeing some kind of battery retainer that somebody had fashioned which looked like a bent wire hanger (it wasn't; it looked much nicer) that wrapped around the left side of the body, under the case, and around the outside of the batteries, holding them in without the outward pressure on the battery door slot. Did anything like that ever get produced in (relatively) large numbers?