I have always loved the cartoon, 'Gerald McBoing Boing' (if you haven't seen it, do so at... http://www.youtube.com/watch?v=uNsyQDmEopw ). In the cartoon, the colors of the scene AND THE CHARACTERS are dictated more by mood than by realism. An element of clothing, hair, or accessory stays consistent in color scheme throughout to provide some continuity and familiarity. I have always loved this look.
As an experiment for a children's book dummy I am writing/illustrating, I wanted to see if this color approach would work in illustration. WOULD KIDS UNDERSTAND THAT IT IS NOT A NEW CHARACTER? WOULD PUBLISHERS BE SHY ABOUT THIS BOOK SELLING FOR THAT REASON (even if kids didn't have a problem with it)?
Here are three examples. Two are interior scenes, both in the kitchen. The other is in the backyard. (Don't try to follow along with the storyline too much - these illustrations jump around - basically it's about a 5 year-old boy who is reluctant to stop sucking his thumb).