Not that I'm aware of. The current coverart for Stardust was commissioned by a fan, and there was someone who sent me some very rough sketches way back in the day, but I lost them. :(

Edit: On the subject of media inspired by the story, I -am- planning on a mod for the upcoming XCOM 2, which I talked about in my blog.

Also, I would love to see fanart but I suck at art in general.

4973888 I hadn't either, and I've since become a diehard fan.