Can we get a roundup of the most common OP tank cheese for preferably minimal investment? From what I've seen:
- Lich Mythic Path for the DR and immunities
- no armor (unless doing a mega-DR tank)
- Cross Blooded Sorcerer 1 level - gets two level 20 Mythic Bloodline Ascensions, usually Undead and Fire, gives DR and many immunities
- Monk Scaled Fist 1, with Witch 1 - gets you Charisma (instead of Dex) to AC, but twice
- stacking Paladin on top of Scaled Fist/Witch for Chr to all Saves (how much investment in Paladin does that take?)
- Mythic Mage Armor (it is self only I believe no way around that(?

- Crane Line up to Crane Riposte, which gives +9 AC in defensive stance while only giving -1 to hit, works with Shields and Heavy armor btw (this does not show on your character, must observe in the combat log)
^ Usually its a few of the above with the rest of the levels in a high BAB melee class.
Any more that don't take much investment but give mega tanking ability? AFAIK you cannot make a tank that comes close to decent AC without taking a few of the above and going no armor.