I don't know how feasible/difficult this would be to implement into the current voting system, but I just thought I'd throw out this idea:
In addition to the first, second, and third place categories, how about a few 'honorable mentions' criteria that could be awarded? Stuff like "Most Creative", "Best Paint", etc.? I'm thinking 2-3 of those per contest, and maybe the categories could change for each contest, just for variety's sake. Basically, they'd be like bonus awards or something, the 1st, 2nd, and 3rd place titles would still be the most important distinctions.