Platinum Games' Kenichiro Yoshimura, modeller on Bayonetta, has written a blog about some features of the character models of Bayonetta and Jeanne. While they share the same "bone structure" it seems Bayonetta has been given more tits and ass. Yoshimura confesses to being partial to Bayonetta while director Hideki Kamiya apparently prefers Jeanne.
Yoshimura also made some interesting notes on the design of Sapienta where he added some nice little details to the original designs including references to Sega systems.
If you're interested in finding out more secrets of Bayonetta's modelling, check out Yoshimura's blog post. Bayonetta was recently released in Japan and will see release in Europe and North America early in January.