Hah yeah AC scales beyond to-hit I think in PvP. I never even really consider that to be honest I don't think I have spent more than 2 minutes doing that my entire time here, just not my thing.
This build obviously has very high to hit, I don't think self buffed you can get much beyond +50 or so. So an uber AC build 70+ self buffed nobody could touch you.
Just got to watch out for those clerics
I would imagine with greater command, harm, commetfall, etc... those Cleric 18/Monk 2 builds will be pretty unbeatable.