Land of Nod does something really similar for their catalog. They have "reviews" from kids on their products. Quotes scattered throughout the catalog. I just looked on their site and couldn't find any. I'm not sure they do it anymore but it was pretty funny.
I made a set of four as a gift for a certain "girlfriend in a coma". Anyone want a set (for free of course)? You might be thinking, "why would I want blank note cards with your kids sayings on them?". If you have to ask then you don't need them! So there. Actually it's not much different than buying a set of cards with famous quotes or inspirational sayings on them. It's not.
I have to send my sister a package so why not include a note? on a card with cute sayings from Emily and Ava? See? I feel I have to explain myself..