Me. 50.
Since Artificers get all their stuff very, very cheap they can have some damn good equipment at that level.
20 Dex, Bracers + 7, and a shield spell alone is 26. Then Bite of the Werebear + Scintillating Scales = 33, then start adding Ghost Ward, +1 insight, Law Devotion... 50. And all of that is on all day except Law Devotion which is only a Swift action, and can be used 4 times a day with Cha 22 (or Cha 14 and one Nightstick, but the character was built in a ruleset that did not allow nightsticks).
About the only weakness a Persist user has is Dispel, except you can Extraordinary Spell Aim AMFs at that level to be immune. Or spellblades, or whatever. Well, there's also a better Persist user, but that goes without saying. The AMF isn't needed otherwise, as the build also has 27/24/27 saves and can reroll any natural 1 once = most stuff at that level has a 99.75% chance to fail against him.