I did a thing!
What I have done is totally unnecessary and some people probably would have advised me against it but I did it anyway. For the longest time I've had an X-Man reproduction cartridge, it didn't come in a Spectravision case but at the time I didn't know that the original came in one either, minus branding. So I got to thinking "what if I take the board from my repro cartridge and put it in a Spectravision case?", and I have done just that. It was oddly easy, in fact the most difficult thing I had to do was cut out the label, since the repro copy had an accurate end label on it. Spectravision and Atari PCB's are fairly compatible with each other, all I had to to was cut away a small portion of the cartridge inside to fit the small divots on the Atari PCB and the Spectravision PCB fit perfectly, if not a bit snugly, into the Atari cart without modification. The most difficult part of the whole process was finding a good scan of the cartridge label, I eventually found a good one, matched the size, and printed it out. At the moment I am still not quite satisfied with the label since the colors are quite off and I made the mistake of using the wrong adhesive to stick it to the cart, it bled through leaving dark splotches on the front, so I'm probably going to make another. Since I printed it with an inkjet printer it's fairly obvious that it's just printed paper with extra wide shipping tape acting as the laminate, it's very fuzzy around the edges, so I doubt it's going to fool anyone, but I don't care all too much. At least it looks authentic when sitting on my shelf and gives me a warm, fuzzy feeling whenever I look at it.
All-in-all the whole thing cost me a total of 23 dollars. Twenty dollars for the repro cart and three dollars for the poor condemned copy of Planet Patrol that had to be *ahem* altered. It still beats buying a legit copy for a couple hundred dollars.