Hello again Alec!
Amereon Press appears to have purchased the 2003 Plume trade editions of The Gunslinger and rebound them in a "Special Edition" hardcover. I could find very little about Amereon House / Amereon Press, and it's unknown to me how many of these were produced.
I say that I enjoy it more than I should because it's simply a rebinding of an inexpensive edition. That said, I recalled seeing it somewhere online in years past and it was like...a splinter in my mind. I couldn't remember who produced it, and it drove me crazy for a short while. When I finally sussed out the name of the publisher, I felt very vindicated.
There was an "A HA! I knew there was someone other than Grant or Viking who made a hardcover! I knew it!!" moment.
Then I was on the hunt for it. I called many small book stores in the US who had it listed on their site, apparently because it's a rebound edition there are some wonky ISBN numbers for it and it's often falsely stated that it was published in 76. Despite being listed, none of these stores had copies available. I tried...15+ stores to no avail.
In the end I bought my copy off another member here, one of only two members who appears to own one. I messaged both members, one replied, and that's the copy you see there.