Oh, sorry, not keeping up with the entire DWV or Brawl thing, been swamped in learning new pipelines and workflows.
Anyway, seems like you can do a Beauty pass? In which case, if it can be composed, I would suggest doing what
Hboybowen showed. Using a set of Toon shaders, and applying sketchiness in PS or such.
Might not help, I don't know, but in games like Borderland, all the sketchiness was created by textures, meaning it was the diffuse texture only. The outline was a simple flat shader, but the inner workings were all diffuse painted.