I would imagine it being in an ad for the site rather than on the site itself - in its entirety at least.
Actually, I know a few decent cartoonists on DeviantArt, and maybe I can commission one of them to draw a few images of Carnivorous's Mitch in different poses that could be mixed and matched on different parts of the site. For example:
- Main banner
- 404 "Not found" page
- Downloads page
- A few extras for frontpage news, holidays, etc.