What about the buffs that you get from whips? Snapthorn, Durendal and Dark Harvest all give you a buff on hit that increases attack speed even more, though I doubt it would be practical for any weapons other than those three.
I've got this one set I've become pretty attached to, I call it the blizzard wizard.
Wizard Hat - Sky Blue Dye
Diamond Robe - Cyan Dye
Winter Cape - Sky Blue Dye
And a Blizzard in a Bottle (optional but fits really well)