I just thought of another idea, its a bit rough but what you could do, if the rims are alloy, is find a good alloy welder (most sheet metal places can weld alloy) weld up the holes and the hollows in the back then send them to and engineering shop for re-machining and re drilling, it will be very expensive but i supose that depends on how much you want those wheels on your car, get a quote first, i gaurantee you'll shit your pants when they give you a price.