Darksight Helm has level 5 cloak of shadows (30 charges) which would raise your attack by 22% and lower an enemy's defense by 27%. Repairing charges would be pretty expensive, but if you used an ITD item and just used the charges on uniques/super uniques/bosses, it may be do-able.
As well, probably a better way would be having a CTA (Call To Arms) on switch, with a potential +4 to battle cry, an anihlus and +2 from some other source, would bring you to a level 7 battle cry, reduceing the enemy's defense by 62%. Again this would be great in combination with an ITD main weapon, and using battle cry for uniques/sup. uniques/bosses. At least with that you woulden't have to pay the crazy repair costs for charges. Plus the range on battle cry is pretty much the full 800x600 screen. As well, battle cry would also decrease the damage of any monster under it's effects.