O'k so as promised I made the sample of my idea today. I only made this one as a 6" size because of the amount of paper it will take to do the full size 12" one. I have had a circle week and thought Star Album. It works fairly well, If you don't want to tie it together to form the complete round it could be laid flat on the cover to form a half circle or maybe you can hang it if not. It was easy to make as I have the Cricut to cut the circles, maybe a bit longer project if you have to cut by other means.
You cut circles in three sizes per "page" with 1/2" difference between sizes and one circle 1/2" bigger than your largest to make the cover. I sandwiched the ribbon between the pages and the cover to keep it in place.
If there is any interest I will post some instructions but if you look at the way my Star Book is made it works on the same principle of only gluing at the outer edge to make each page stand away from the last one.