I've tried to find them to no avail. I'm guessing the box sets just aren't made anymore, but I figured it's worth asking in case there's some obscure one out there somewhere.
To clarify, I'm looking for a more recent Linux version. I know the older ones can be found on auction sites and the like.
I was speaking of the Debian "full archive" 21-DVD sets: https://www.shoplinuxonline.com/debian-full.html
But I don't know about how they package it, so it might not be a "box set" as you describe.