While I'm willing to look at anything, I have an image in mind that my meager photoshop skills cannot bring to life:
At the top of the cover is a picture/drawing of Voidgaze, the city on the edge of the world. It's towers reach higher the closer to the void they get, trying to catch the slightest sunlight from the world's distant central sun. Hardy plants are cultivated in greenhouses and walkways connect the highest towers. The building materials are mostly stone and wood.
Just beyond the city, floating in the void, is a white tower and small walled courtyard. This tower is tethered to the rest of the world by many chains of various thickness.
This image fades into the title/author name.
The bottom half of the image includes the three protagonists walking towards the reader, an indistinct shadow rising behind them. The shadow could be either a spider-like creature, or a thick-set, bearded man.
The protagonists are: a female uniformed guard (green coat), a gorgeous, innocent, young male guard, and a demon who looks like a Pathfinder Kelpie in an impeccable black suit.
*Still willing to see anything, but I figure that gives you a good idea of the main imagery.