Here are two of my favorite "Long Books" I made last year from paper I got at Binders. The binding is called the long stitch but I call them Long Books because of the height. The green one has some coptic stitching as well. They are 10.5 x 4.5.
These books take 4 to 5 hours to make. But, they are worth it!
Paper: Decorative Papers from Binders and from inside a vintage childrens book, resume paper for inside pages