design sheet or back page for a new artist book?

This one was crying out to be created. It popped into my head and took up permanent residence. Initially it was going to be a stand alone design sheet but now I am considering another option. There's an awful lot of empty space on the left hand side which definitely could be filled as this design sheet develops but now I'm thinking a little booklet might live on that side, making this the back plate for said little book. What do you think? You know how much I love a little book.....