I think you may be onto something. We know we're getting settings in a heretofore unseen (in 5e) format. A boxed set containing a setting-specific player's guide, DM's guide, and monster book seems to fit that bill, as well as the $165 bill. I could see such a boxed set working well for Dark Sun, since a big part of its identity is lacking certain races and classes that are core in 5e, as well as having a lot of setting-specific new options for races and classes. And such a release would be a great place to expand on psionics... Damn, I hope this is it!