Nah, I'm really redesigning him from the ground up, and (for the most part) making his face look like zim's voice could very easily come out of. That's the problem with Jonen's style, while awsome, it's hard to tell one character from another with ful color. There's no detail to make a character LOOK like a character. If I were to model A JV zim, it could have just as easily been some other irken soldier that looks just like him in the background of the first episode (there were a lot of clones there). I'm sketching out what they would look like on paper with nothing in my head but their voice...
I do admit, I might need put in a little elements of Richard Horvitz in his face, too.
But that guy is AWSOME.