A 10th level barbarian with a 26 AC? The heck? I suppose if you put all your money in defenses (you are supposed to have about 49k in money at 10th level), sure. You could have +3 mithral full plate (19,500), +1 animated heavy shield (9,330), +2 ring of protection (8,000), +2 amulet of natural armor (8,000), and gloves of dexterity +2 (4,000), with a starting Dexterity of 14. You end up with an AC of 31 (+11 armor, +3 shield, +2 deflection, +2 natural, +3 dexterity).
Of course, when I made a character with those feats, I had a Dexterity of 8, wore no armor, and liked to have the party wizard enlarge me. With my base AC of 9, at 6th level I could be large (-1 from lower Dex, -1 from size), charge (-2), be offensive (-4), and recklessly raging (-4), while combat bruting (-6). My AC reached -9. *grin*
Of course, with a falchion I had a +18 attack bonus (+6 base, +1 weapon, +4 base strength, +1 enlarged strength, -1 size penalty, +3 rage, +2 reckless, and +2 charge), and dealt 2d6+25 damage (large falchion, +1 weapon, +6 base strength, +1.5 enlarged strength, +4.5 raged strength, and +12 power attack).
At 10th level with the character, I would have spent my money on my weapon, on potions of flying and enlarge, and a belt of strength and amulet of health. And lots of potions of cure light wounds.