4.5 years later, I am still trying to think of something. I guess maybe using the front of the card as decoration in a scrapbook and then save the notes/signatures and put them in the scrapbook along with pics from the shower. Good Luck and Congrats!
you might want to try to start a scrap book, i know when i found out i was pregnant and then had my daughter i started a scrap book and now she is 9 and she has been putting things in the scrap book since she was 6, its something special from the parents to the child and then the child can continue to add things as they get older
One good friend of mine took all her cards from her wedding shower and made them into a collage on a giant poster board. She then placed a picture of her and her husband in the middle, went to the local craft store and had it framed.