You've just got to love assassination

. My kensai/thief dual wielding wearing the gauntlets of extra. spec. had 8 attacks per round with improved haste. When I dumped him right in the centre of some intense action (think frontal assault on monk monastry) his next 8 attacks dished out well over a hundred damage.
By the way, how do you get a pure thief to attack 5 times?!? The only way I can think of is to dual wield (2 attacks) with improved haste (4 attacks) wearing the gauntlets of extra spec (5?). Is this what you mean?