Hey, this looks to be a nice piece. I am sure a case back from some other model would fit this watch, but this would be easiest done by a watchmaker. I guess you should look around in your area. When searching on ebay I found a Seiko 2633-7009 which looks to be the same like yours, but in silver for 35 $. I am sure the case back would fit, although it would be a different color. Or if you insist on the golden color you should search for a donor of the same exact model. Good luck!