Snoopy is used quite a bit. If you buy a Williams Bros. pilot, he can be reworked a bit to make him more realistic. First thing is to not make his eyeballs big saucers. Look at someone's eyes and you will see their top eyelid comes down over the pupil slightly. It's not a big dot in the middle of the eye which always looks garish.

You can use contact cement to add a beard or mustache and a little work with some oil paints will give the skin a more realistic non-monotone look.

Pick up a book by Shepard Paine to learn more about figure painting. The man is a god when it comes to painting models and figures.