In a recent Penny-Arcade news post, Mike K. wrote about how one of the major influences on his art was the work of Stephen Silver.
And after paging through some of the stuff on Silver’s deviant art page, I can definitely see it in the character designs he did for Clerks and Kim Possible.
The style reminds me of the artist who does swoopy minimalist line drawings of celebrities. I don’t know the artist’s name or any specific pieces (if you know the name, log a comment below), but I’m very familiar by the lampooning of the fellow’s w work on the Simpsons. A very memorable portrait of Monty Burns.