Noone seems to have mentioned Planar Shepherd in this build. Have I missed some line where it's been banned? That prestige class really is the most optimal choice for anyone looking to advance Wild Shape and casting, even if you are trying to make a Gish. Sacrificing a grand total of 3 points of BAB is completely worth the Outsider Wild Shape ability.
If you're concerned that it's too broken, maybe talk with your DM about what the class can do in theory, and what you'll actually be doing with it. Gentlemen's agreements ftw.
Chameleon's a very good, non-Wild Shape choice. If you use a trick to grab yourself 9th level spells with the class, you'll have more spells per day than a Wizard, and know every single Divine spell in existence, as well as being able to cast every single Arcane one.