The Soulwarped Tower Shield from the normal Socrethar encounter in Hellfire Citadel looks really good with the Alliance version of the PvP set (never mind the WoWhead screenshot, it's actually white, black and red). It has the same sort of ridged texture, the black trim on the side of the shield matches the black trim on the armor, the raised plates with a circle cut-out pretty much matches the shape of the pauldrons, and the red orb would go well with your combo-breaker belt.