This is a free vector renderer for Blender.

http://freestyle.sourceforge.net/

Very cool!

And for people afraid by Blender

Do you know that the free Sketchup has a huge of differents "free style" ? ;)
http://sketchup.google.com/intl/fr/

So just export in skp format from Moi to Sketchup, reload it in sketchup, choose your style!
That's all :)
you can't find more simple! You can also with Blender but you must learn Bender :D:)
With Sketchup nothing to do :)

from a model found on the net ;)
before

(here i render with Kerkythea or Twillight render or Renderin or Podium or Light Up etc...all plugins of Sketchup )





after apply a preset style!

But is the sketchup result vector?

Yes
You can select any segments, faces, volumes "sketched" inside Sketchup

No sure that you can render the sketching! (not tested)

So save as image and you can vertorize the result with Inskscape
http://inkscape.org