What is the base damage for bound weapons? Are they confirmed to be daedric-grade? I'm not entirely certain... I tried checking the actor value "meleedamage" but it returns 0 all the time no matter what weapon is equipped.

They're like steel unimproved and like Daedric with the perk. Note that the bow uses free Daedric arrows so that's big boost over normal arrows, 24 damage compared to 8-12 of normal.

edit: apparently only the sword is like steel/Daedric, the bow is better.

http://www.uesp.net/wiki/Skyrim:Bound_Weapon

I remember reading somewhere that they are essentially the second most powerful type of a weapon. That Daedric was better.

edit: But after looking at the page that Cheshyr linked, it really doesn't look to be that!