I love the artwork but from my knowledge hasn’t been reused ever again. (cleaned) If someone owns it, would it be possible for you to scan/take a photo of the artwork so we can view it in higher quality?
Flea markets in Japan if you're in the country, otherwise auction websites like Yahoo Japan auctions. It comes up from times to times, like many other things.
That said, personally I'm not comfortable with scanning artwork at scale, in a similar vein to our "no episode scans" policy on SKnet.