Our DM is sending us to war as generals of an army each of us leading a 100-200 man squad. I am building my squad around having a ridiculously high AC.
I am equipping the squad with Full Plate +5 and tower shield +5 giving a +23 to AC from that.
I have found a few feats such as:
Coordinated Defense: Whenever you are adjacent to an ally who also has this feat, you receive a +2 competence bonus to your Combat Maneuver Defense. This bonus increases to +4 if the creature attempting the maneuver is larger than both you and your ally.
Covering:When you use the total defense action while using a light, heavy, or tower shield, you can provide a cover bonus to AC against all attacks to an adjacent ally your size or smaller. This cover bonus is equal to your shield’s shield bonus and lasts until the beginning of your next turn. your shield does not provide a cover bonus to reflex saves.
These are good but I am not sure if I could get NPC with the Covering feats as it requires a BAB of +6. A squad of 100-200 lvl 6 warriors would be a force to be reckoned with so I am not sure if our DM will be having them be that high of a level.
All information I have gathered is from http://www.d20pfsrd.com/