I made my own for DD a few years ago. Not sure if you want to go to all that trouble.
I bought a small scrapbook at Michaels. It's about 7 inches wide by 4 tall. Then I went to a Disney clipart page and found one picture for each character DD liked or that I thought we'd see. I made labels with the names in Word and glued them all in the book, in alphabetical order. I used one whole open-book page (really 2 pages) for each character. I decorated the page, added the name and photo to the left side and left room there for the autograph and then left the right side for a picture of DD with the character.
My daughter loves the keepsake book with the autographs and her picture with the character. The characters really got a kick out of seeing their own personalized pages.
Just a thought if you want a little project for yourself!
This reminds me...I need to get on this project for DS for our next visit. He hasn't had an autograph book yet!