Random idea hit me in the middle of the night and I had to plug some more artwork into Topaz Megapixel and see what spit out. A few could use a little cleanup if anyone's willing to partake of the task. (Hellin for example has some weird artifacting on her face) But I think you'll find these suitable for all your 1920x1080 desktop needs.
EDIT - I've gone ahead and added the Gatekeeper image as well. It's not the same level of quality as the others, but it's currently the best image of that artwork we have.