A letter or document: something between a sign and a book

I find signs and books quite clunky for writing messages. A sign often doesn't have enough space, and a book has relatively small pages, and needs to be put in a chest.

I would like a note, document or letter, just a piece of paper that you could fit quite a bit of text on, and then stick to a wall or put on top of a block to leave as a message for a friend.