I also don't find it out of line. And the thing with an AC whore build (as my friends and I call it) is that you still need some way of getting enemies to attack you. I've had lots of PCs that went for massive AC, often sacraficing damage and hp in the pursuit of it, and I can say from experience...nothing feels worse than pimping out your defenses to the max, only to be utterly ignored as the enemies seemingly all attack your allies instead of you. All dressed up with nowhere to go, as it were.![]()
If the bad guys can't hit a PC in melee, then they'd turn to spellcasters with Area spells or ranged touch attacks.
My party has a PC like that - it's an elf fighter/paladin/champion of Corellon. Plus, he has a defending sword. He took Combat Expertise and Improved Combat Expertise, and with his PrC ability to wear heavier armor & keep his Dex bonus, his AC can legitimately get up to the low 60s now. Of course, he has lost +16 off of his BAB so can't really hit anybody with an AC:30 or higher... and, even if he does hit, he does not do nearly the damage the dwarf fighter or goliath barbarian can do.
He did take the "Goad" feat as well in order to try to get bad guys to attack him first.