I love this! I'm planning my SIL's baby shower and thinking of going with a 'nest egg' theme, this would be great for a guest book.
Also, I think it's cool that you are learning bookmaking from Esther Smith's book, I took an Artist's books class with her a few semesters ago (she teaches at the School of Visual Arts) and became obsessed! She also has another book called Magic Books & Paper Toys, which is equally as awesome. I don't much care for her as a person
(not like it matters) but her books are really helpful.