Also, for the OP:
Cloistered Cleric 5/Dweomerkeeper 4/Shapeshifter 1/Planar Shepherd 10
19/20 casting, Wild Shape as a 30th level Druid, Supernatural Spell 1/day, and the usual Cleric goodies. Take the Transformation domain so that you can grab Polymorph et al.
Or, for more cheese (lots more cheese):
Wizard 5/Incantatrix 3/Shapeshifter 1/Planar Shepherd 10/X 1
Use Alternate Spell Source to get PS casting added to Wizard. Use Metamagic Effect to persist any spell-like abilities (or supernatural abilities!) you happen to like from your forms.
For extra super-duper cheese, pick some plane that has every creature imaginable as its native inhabitant (The Realm of Dreams would qualify for this, and would also have a nice time trait to abuse).