Fighter/Rogue uses short sword, tower shield, Dodge, Combat Expertise, Shield Specialisation for an AC of
10 + 1 (dex) +8 (full plate) + 5 (Expertise) + 4 (tower shield) + 1 (Dodge) + 2 (Shield Spec) +3 (fight def) for AC 34 at level 6 without any enhancements...
In case he wants to hit something, he's aiming for ITWF with two shortswords or shortswords and smaller shield (misses on the tower shield AC bonus but uses TWD) for 4 attacks... he will only hit on a natural 20, but plans to make up for it with full Power Attack on 4 possible attacks.
Edit: use of the revised Shield Spec feat from KoK PG.