I was looking around at work today (I know - I'm bad... but it was so slow today, I couldn't help it!) and I found a website with a bunch of different card box designs. I think she makes them and sells them (they are expensive, IMO) but if you're looking for creative ideas... maybe you'll find some inspiration on here. Either way... they pretty nice boxes.
http://creativecustomcardboxes.blogspot.com/search/label/wedding