The Animator's Wife had this problem when she went to Ireland in 2010 and bought some local yarn spun from real Irish sheep. It was surprisingly hard to find, so she wanted it to be used for the exact perfect project--something that might last forever.
And so she ended up using it to make a book cover, but not just any book cover. To make it just a touch more interesting, she worked it so that the book cover would make the book look like a purse so that the book might be easily toted around.
As it so happens, the book we covered is The Animator's Wife's bible, but this technique could also be applied to personal journals, sketch books, scrap books, or any other book that has special meaning to the owner.