I produced these images of Wisconsin's Driftless Area for a client. The colors in the first version come mainly from the National Land Cover Database. The second version showcases just the relief. This actually began as an accident; I was turning layers on and off in Photoshop while working on the first version, and I happened to turn off everything except the relief. It looked pretty great, so I stuck with it.

The relief was generated in Blender, mixed together with a texture shade, which makes a great enhancement. The relief + texture shade gives a hint of a hand-sketched effect, I think. A little Photoshop filtering could potentially take that farther.