If I had lots of money, I'd throw a lot of it at this:

I'll be happy to send a signed copy of the strip in which the person appears (which will likely be in the local weekly newspaper) but only on the proviso that the person in question doesn't get mad or otherwise grow to despise me if their likeness is construed as satirical, incorrect, unflattering or in any way unliterary. I'll do my best, however, to maintain veracity and allegiance to the general rules of propriety (unless, of course, the winner offends me, in which case he/she may appear as any variety of disagreeable and distasteful ruffian.) The winner should also realize that if his or her character ends up contributing significantly to the development of said story that the author/cartoonist cannot be held liable for any confusion, affront or life complication said appearance might subsequently engender."