Ways to find and purchase out-of-print / rare / old supplies?
If you are looking for something like this that you can't easily find through most normal sellers I would try contacting the Customer Service departments of larger sellers like Star City Games or Channel Fireball and see if they have any way of finding the item in question for you. I don't know if CFB does this, but SCG does have a process for managing user requests, they might not have it in stock now, but knowing that you are interested in buying one means they are likely to acquire one if they come across a seller.