I love this idea. An envelope guest book. You just take a store-bought scrapbook/album and glue envelopes into it. Lay out colored pieces of paper for guests to jot notes down on, and then they can place them in the envelopes.
Will You Be My Bridesmaid Card, Bridesmaid Card, Maid of Honor- Custom made and personalized
For MOH duty: Have each bridesmaid, mother, mother-in-law. create a scrapbook page which includes a letter to the bride along with pictures. This is something she can read the night before the wedding. The last page could be from the groom!