It was recently brought to my attention that Zak Smith produced a series of ekphratic artworks that respond to Gravity's Rainbow. The website that hosts the images is here. Smith himself explains:

"Most of the pictures are drawings-- ink on whatever paper was lying around, but there are also paintings (acrylic), photos I took, and experimental photographic processes. I tried to illustrate the passages as literally as possible-- if the book says there was a green Spitfire, I drew a green Spitfire. Mostly, I tried to make a series of pictures as dense, intricate, and rich as the prose in the book. The entire project was shown in the Whitney Museum's 2004 Biennial Exhibition of Contemporary Art and is now in the permanent collection of the Walker Art Center in Minneapolis."