Ben Towle has posted some sketches on his blog of a work that is not so much in progress as on hold: A graphic novel adaptation of Cherie Priest's steampunk zombie novel Boneshaker. Towle has an interesting perspective:
As I looked to working up some drawings for this, I made a deliberate effort to avoid for the most part visual references that dealt with steampunk and instead sought out historical imagery from the American Civil War. My approach to this was just to forget about “steampunk” entirely and to approach the project as an alternate history of the Civil War.
In the end, what got him was the zombies, or rather, the daunting task of coming up with a visual take on zombies that hasn't been done a million times before. He hasn't given up, though, just put the project on hiatus for now... and he's looking at some other books as well. In the meantime, enjoy the art—he has a few more pieces posted at his blog.