I'm a fan of the dual wielding myself, but for raw AC potential, One defending weapon and the tower shield i mention would be a higher AC (5+9 instead of 5+5) As for the breastplate, as i mentioned, highest Armour AC does come from full plate:
Breastplate: 5 AC / 3Dex (5 Dex Mithral) 8/10 AC...