Cartoonist Chris Schweizer (the Crogan Adventures series) is also a professor at the Atlanta branch of the Savannah College of Art and Design and that combination can result in some cool things. Like this Crogan maquette he sculpted as an example for a character-design class.
Schweizer talks about the benefits of this kind of exercise when creating characters for a comic, but is also mindful of the dangers:
I spend a LOT of time on preproduction, but it's a means to an end. Never, ever, ever let it be the end. It's self-indulgent, and benefits you nothing. ALWAYS make sure your concept work is leading to stories. Otherwise you're just playing with yourself.