imo, a complete diff cover replacement is a lot better than just a ring
as for local places, I've contacted a few in the past about doing skid plates, and none of them have anything pre-made that you can order and bolt on, they all seem to want to do on-vehicle fab, and let you know how much it costs after it's done. (I haven't even been able to get a rough ballpark estimate from any of the places I've contacted) That's why I suggest using somebody that already has it all fabbed out, that you can just buy and bolt on.