Hello Pixologic,
at first thank you for ZBrush it changes my life and my everyday work! 
A few weeks ago I’ve seen this on the web and it blows my mind:
It would be great to render with the possibilities of StyLit in ZBrush, or use it as a posteffect. Don’t understand me wrong, MatCaps are really great and powerful! I guess it will be a paradigmatic shift in the creation of 2d art with ZBrush if you integrate this methods.
Give this guy and his team the money he deserves for this.
Best,
Dirk