My uncle had stock wheels on his old '89 911 Turbo vert that were 2/3 wider than stock. They were made out of 2 sets of rims by cutting the inside lips off of one set, cutting right behind the spokes of the second set, then attaching the inner piece of the second set to first set.
The car came that way so I have no idea who did it or how they did it, but it is possible.