From the Conquest program:
http://www.youtube.com/watch?v=Ys6zON34qGg&feature=relmfuGreat video, it shows some daggers from the XII to Early XIV Centuries (Warband`s time)
3:25 Scramasax: German, French, Viking Knife enough powerful to penetrate Medium Armor easily. able to slash of thrust
8:20 Rondel Dagger: European, mainly French Dagger from Early XIV, only for thrusting.
6:52 Quillon Dagger: European dagger from Late XII, useful for slashing and thrusting
6:24 Misericord Dagger: English, German dagger from Late XII, only for thrusting.
http://en.wikipedia.org/wiki/BaselardBaselard Dagger: English/French Dagger from Middle XIV , mainly for thrusting.
I think more daggers and knife would be cool