Just stumbled on an interesting site, Erth Chronicles, where Richard (James Johnson) is allowing artists to submit their original works for posting on the site. He’s the author behind the Erth Chronicles fiction (Book I, The Enemy’s Son, is available for purchase now), and he’s inviting artists to submit their works to him for posting on the site.
From the little bit of information available on the site; it appears that the licensing provides joint rights to Johnson and the artists if the art is posted on the site, but if Johnson wants to use the material anywhere else, he has to obtain permission from the artist. I presume the artist can use their art however they want, but that may not be true.
This is a similar approach, though on a smaller and more limited scale, to what we’re doing at Runes of Gallidon. Our licensing terms are different, and we have a multimedia approach (fiction, art, RPG modules, digital games, etc.). But the idea of collaborating together to build out a world is the same.
Nice to find another example of quality collaborative world-building. Best of luck to Johnson and the artists involved!