We had a lovely baby shower for my friend Jenny on Saturday. She has a little boy due in the next week or so. If you are a Regency-era literary type, you will appreciate the invite I did for her.
I wanted to do a table centerpiece and my daughter thought the phrase 'diaper cake' was the funniest thing she'd ever heard. Once I showed her how it was assembled, she warmed up to the idea. She even rolled up all the diapers for me! I just had to secure them (I used clear elastic bands) and then tie the ribbons and add the decorations. So I definitely recommend finding yourself a little moppet-helper before taking on this project.
Also I recommend the Luvs or ShopKo brand diapers because they are mostly white and you don't have the silly characters all over your pretty cake. Unless you are into that sort of thing. Also, now that I think about it Jenny, you should take that green ribbon-bow with the flower from the top tier and make it into a barrette or headband for Savvy. Hot glue the white flower on so it's more secure before you do it.