Joe at Palm Gaming (RIP) did them back in the day. I think
@Potsie1 had purchased some engraving equipment some time back and was thinking of possibly doing these but I believe he decided not to (equipment wouldn't handle the cage size).
I always liked the look of them and drooled over
@Redbelly 's shown here from a few years back.
If you find someone more reasonable & reliable keep us informed, I would maybe drop for one.