i did do those rendering to illustrate a video tutorial about my workflow to achieve this kind of look in maya 2009 with mental ray .

having started my cg career with lightwave , i was very fond of the cell rendering possibility that this software have to offer ,
being now a maya artist i really wanted to be able to duplicate those result , i tried the paint effect method but at the end of the day .. i do prefer the result and ease of use of mental ray
each picture i done with 2 pass one for teh color and one for the outline rendertime for each pass is around 30 sec
then a little bit of post processing is added in photosho cs or in digital fusion