Ken's got a point... carmelized sugar is what a lot of people use to 'strengthen' in contests like this, or even to decorate. I remember watching a Food Network special a while back that was done completely with sugar, with a Cirque de Soleil theme to it. Very cool, and crazy to see the kind of statues they could put together.
I've also seen people do this with peppermint sticks, cinnamon sticks, etc. It's possible. I've also seen a graham cracker house with a cheesecake roof and chocolate shavings for shingles... needless to say it collapsed from weight, but was still delicious.
