In bear form I am able to get 17 AC.
12 AC from natural armor
3 AC from mage armor (cast by Gale *before* I transformed, but remains when I switch to bear form)
2 AC from shield of faith.
Its not entirely clear to me whether these are bugs or intended (although in this case the shield of faith is definitely a bug, because Shadowheart was removed from group after she cast it, and is sitting in camp where she cannot fail a concentration roll, definitely broken IMO).
I do suspect that 17 AC in bear form will be unbalanced at very low level, at least. I *think* that the mage armor should set AC to 13 + Dex bonus, which implies to me at least that it should not stack with the bears natural armor. I would be happy to receive informed correction on this point though.