please note that putting the fist blade in the main hand instead of the offhand will make your kill animations.....interesting. (Slitting someones throat with the guard, and stabbing someone with the pommel, among other things) this is because the offhand weapon is reversed. you can use the main hand version (called Trench Knife) in both hands, so if you don't want to deal with this, you don't have to
the off-hand block version has a few known issues i am attempting to resolve:
Using the offhand block fist blade in the main hand will only show a fist.
Using the offhand block fist blade will sometimes mess with the kill animations.
in order to show the blade better, i used TS' "1 HD weapons on back TS Edition"
http://skyrim.nexusmods.com/downloads/file.php?id=6276
Thanks go out to Urwy for his Models and Textures