Okay, I think idea is way cute!! Instead of the traditional guest book option you could have a "wish tree".

I came across it on Here comes the guide. I always thought the traditional guest book was so boring. How many times do you think people pull out their guest book just to look at signatures. When you use a Wish tree you are able to put your "wishes" in a srapbook and/or photo ablum of your wedding guest celebrating your big day.