Quote Originally Posted by hamishspence View Post
Some prestige classes get extraordinary abilities that boost their Bluff checks (thrall of Baalzebul, for example) but it's hard to think of any that gain total immunity to the effect of spells like Zone of Truth.

Since Zone of Truth is technically a Mind-Affecting spell, anything that grants Mind Blank as an extraordinary ability would qualify.
The best fit I can think of or find is the Spymaster class from Complete Adventurer. Taking levels in it gives you a certain number of cover identities, which become capable of fooling any and all divinations at the highest (7th) level of the class. Nothing says that one of your cover identities can't be "yourself, except not an evil mastermind," and the prerequisites consist entirely of ranks in Aristocrat class skills.