I am a major FAN of Carrara 5's NPR rendering feature- in fact it was the main reason I bought C5... so I was really INTERESTED to see that an ACADEMIC PROJECT has developed NPR features that look similiar to C5's NPR---but BEYOND what C5 can do-- leading me to the HOPE that maybe C6 will have something like THESE...

FREESTYLE is FREE to download and is based upon the Renderman shader language...

http://freestyle.sourceforge.net/GALLERY/dirindex.php