I've been trying to put together a ZBrush/Photoshop setup to render sculpts that look as if they were a sketch. This is 98% ZBrush, the other 2% being an adjustment layer in Photoshop to whack the image into an appropriate color space and value range.
Why even bother with this? Boredom as I mentioned above for one. The other reasons, eventually I'll likely use this as a render pass to comp on top of paintovers for some outline effects and such. The other use case would be when I need multiple drawings of the same thing from different perspectives. I reckon something like this would serve as a good starting point.
Anyways, I'll share the project files once I wrap things up with the notes and such, :)