Do any other joysticks use a top mounted restrictor like this??
So, nothing besides after market cruft. Figures.
Not exactly so. The original WICO 4-ways, original Pacman stick, and probably some others I can't think of ATM. The WICO also had diamond shaped restriction in the lower portion of the base, probably for extra wear factor. These were not add-on restriction, rather molded or cut into the base.
Placing the restriction at the bottom of the Dominux8 is not possible, without many changes to the design and the parts. It would add significantly more cost, increase the below panel depth footprint, and likely negate the feature of the installer being able to select the shaft length they desire. And after all that, the net result would be only to solve the dustwasher issue, which isn't even an issue for most. Simply adding spacers is a better, and more economical alternative, for those who need both restriction and the dustwasher below a metal panel.