Today, while serfing the web, I ran across a pic of Father Callahan by Michael Whelan. It is recent, and shows him holding an old 70s copy of Salem's Lot. This is Callahan from the later DT novels, when he discovers he's a character in a King novel. After some searching, I found out that this pic is one of several that MW was commissioned to paint of major characters form the DT novels. I found what looked to be another one, this one of Roland. Someone on the DT forum was using what looked like one of Oy their avatar. Then I found a bunch of Whelan sketches, mostly of Roland, Oy, and Jake, including one of rat-faced taheen, someone had posted on the same forum. None of them appear in any edition of DT books that I am aware of. They are called maraques, or something like that. I found more posted on the forum, by other artis's including two by Ned Dameron for the First Edition of the Wastelands, by they are not in the edition I have.
What are maraques? In what editions do they appear? Was there a special print run with these drawings in them? Were they done in unique copies of these books, and lucky few got ahold of them? Are commissioned artwork by fans? What?
I think you may mean marques. The limited editions had additional illustrations that were not in the mass market releases and my recollection is that when some of the later printings of the books were rereleased by Donald M. Grant, they had illustrations that were not in the earlier versions done by Phil Hale and Ned Dameron. We also commissioned Michael Whelan to do several illustrations for Discordia and those were not the same as the books.