While there may be a few nickle plated shells that were sold as aftermarket replacements in the day they would be far in between. You might keep your eye on ebay for after market hot rod shells. If they measure out the same one might work. If you find one that could be plated as Farmallcub49 suggested, plating is going to run in the $100's of dollars. Hope you find one, should look great on your milk wagon.