Actually, I don't think flurry works.
The power attack for daggers doesn't seem to change in speed, while the power attack for swords becomes noticably faster for each rank in flurry, and a dagger + sword is amazingly quick compared. Gives me some doubts about whether the dual wielding power attack damage bonus applies either
Flurry doesn't work for dual daggers. If you put a sword, axe or mace in one hand and a dagger in the other, it will work fine. Mace in one hand and dagger in the other works best for me, Mace for the damage and 75% armor ignore, and dagger for the 30x damage backstabs.
On a related note, it seems Mehrune's Razor is bugged or has an unlisted bonus. I use it in my off hand while dual wielding, and I attack twice as fast as dual sword, or sword and dagger!
Can anyone with a character with 2 points in dual flurry and a Mehrune's Razor confirm this? I wanna know if it is a bug just for me.