And my version of the Dwarven Defender (using some of the ideas we've come up with):
Requirements: BAB +5, Shield Specialization, Active Shield Defense
HD: d12
BAB: Full
Saves: Good Fort and Will
Class Skills (4+Int per level): Balance, Climb, Concentration, Craft, Diplomacy, Heal, Intimidate, Jump, Knowledge (Dungeoneering, Religion), Listen, Profession, Ride, Sense Motive, Spot, Swim
1. Defensive Stance 1/enc, Defender's Fury (15)
2. Bulwark of Defense, Diehard 1/day
3. Defender's Fury (20)
4. May I Have Your Attention, Diehard 2/day
5. Defender's Fury (25)
6. Defensive Stance 2/enc, Diehard 3/day
7. Defender's Fury (30)
8. LOOK AT ME!, Diehard 4/day
9. Defender's Fury (35)
10. Diehard 5/day, Impossible to Kill
Defensive Stance - Once per encounter a Dwarven Defender can enter a Defensive Stance as a free action (and can enter it even on others' turns). During this stance the Defender gains a +2 bonus to AC, +4 if fighting defensively, and +6 if using the total defense action. Furthermore he gains a +4 bonus to Str, temporary hitpoints equal to his Con modifier times his HD, and SR 11+HD+Con modifier. While in this stance a Dwarven Defender can't move more than his base movement speed without ending the stance. This stance lasts 5 rounds.
At 6th level the bonuses to AC go to +4, +6, and +8 respectively, and the bonus to Str increases to +8. At 6th level a Dwarven Defender can enter this stance twice each encounter (allowing him to break out of the stance if necessary and be able to re-enter at a more advantageous position).
Defender's Fury - Whenever a Dwarven Defender's ally would be dealt damage add that amount of damage to a pool called his Fury pool. For every 10 points in his Fury pool he gains a +1 bonus to attack rolls, and for every 5 points in his pool he gains a +1 bonus to damage. This pool gradually depletes. At the end of any turn during which the Dwarven Defender got a bonus to attack or damage from this ability reduce the amount in the pool by 5. At the end of any turn during which none of his allies are dealt damage reduce the amount in the pool by 10. At 1st level a Dwarven Defender's Fury pool can only hold 15 points, but this increases by 5 at every odd level thereafter to a maximum of 35.
Bulwark of Defense - As Knight.
Diehard - Dwarven Defenders gain Diehard as a bonus feat (as mine). Dwarven Defenders gain additional re-rolls against the effects specified in the Diehard feat as the table indicates above.
May I Have Your Attention - Whenever a Dwarven Defender attacks with a melee attack, whether he hits or misses, the attacked creature must succeed on a Will save (10+1/2 character level+Dwarven Defender's Con modifier) or attack the Defender with a melee attack on its next turn (incapable of other actions). If the Defender's attack hits increase the save DC by 4.
LOOK AT ME! - As a standard action, once per encounter, a Dwarven Defender may unleash a battle cry subjecting all enemies that can see or hear him within 100ft to a Will save (10+1/2 character level+Defender's Con modifier). Any creature that fails its save must attack the Defender with a melee attack on it's next turn (or spend it's turn getting as close to the Defender as possible), and for the next 1d4 turns.
Impossible to Kill - As long as a Dwarven Defender is in Defensive Stance he cannot be killed by hitpoint damage. Whenever his negative hitpoint total would be low enough for him to die he can instead make a Fort or Will save (whichever he chooses, DC 15+1/2 his character level). If he succeeds he remains standing and able to fight until he next dealt damage. Increase the save DC of this save by +3 for each save he has previously succeeded against.