This idea is an update 9 flavor shield build.
The biggest problem with shield builds is the loss of DPS.

Dwarf Barbarian 18/Fighter 2

S 18 + level ups
D 14 (or 16 if dwarven defender comes out if you want the AC)
C 18 (or 16 if dwarven defender comes out if you want the AC)
I 8
W 8
C 6

Skill points into intimidate, balance, etc.

Feats:
1 THF
3 shield mastery
6 ITHF
9 improved critical slash
12 GTHF
15 improved shield bashing
18 toughness
1 PA (take fighter 1 sometime after level 1)
2 cleave (take fighter 2 whenever you want to qualify for frenzy)

Against a 50 damage hit you will take 41 (DR 9/-) * 0.8 due to shield mastery (with tower shield) = 33 points of damage.

If you have a 50 strength your shield bashes will do (with a plain +5 shield):
3.5 base + 5 power attack + 5 enhancement + 20 strength
= 33.5 * 1.25 (regular crit on 20, frenzy crits on 19-20) = 41.875 + 21 viscious
= 62.875 average damage/shield bash
= 12.575 average damage/swing added
That will help make up for some of the loss of damage from *1.5 strength and double power attack from using the dwarven axe instead of the greataxe.
Of course this won't compete with a sword of shadows, but you can always go between tanking and DPS mode depending on the situation.

Alternative build options would be a human with dwarven axes or bastard swords instead. You'd have slightly less hp/saves/ac but gain healing amp.