I found these:
http://www.placetile.com/messagetiles.htmlI think they're very cute, they could be used for just about anything and they're reusable because it's tile, comes with a special marker and you can write and erase as you please!
I might get some for my bridal shower, next to the sign in book, or to the "leave the bride a message" table (hopefully with that darn typewriter!).
The site also has placecards, and cheese (or food) signs. Hope this helps someone!