Ok, currently found an insane exploit in beta which allows you to stack your top end damage as melee, do it quick before it gets hotfixed. Here's how to do it:
While on the Banshee's Revenge quest in Icecrown at Balagarde Fortress (dont necessarily need to be on it, need someone to spawn the quest mobs) Overthane Balagarde's drake will occasionally throw frost on the ground, similar to a frost trap. All you have to do is run in and out of it, and everytime you gain/lose the debuff, your swing timer gets lower and lower, but your damage keeps stacking.
Screen:
Currently it lasts through death but does not persist through zoning =( Have fun owning in Wintergrasp or while questing.