I have not been really thrilled with Skyrim's dual weapons system. Not in the least because you cannot hotkey your off hand weapon to appear in your off hand. But I do like the idea of a character who fights with a pair of daggers, or short sword and dagger.
So I created a shield that looks like a dagger. It acts just like any other shield, bashes, uses the blocking perks, etc... But it has the mesh of a dagger, so it looks like you are using a dagger to block with.
Here is how to create one from any dagger in the game:
Make a copy of the dagger's mesh file and rename it. Open it with Nifskope, and go to the root node. Beneath it will be a string called NiStringExtraData.
Its text will say WeaponDagger. Right Click on it, select Edit String Index, and manually enter the word: SHIELD.
Save your mesh file.
Go to the Creation Kit. Copy the entry for a shield and create a new one for your parrying dagger. Replace the mesh with that of the dagger you just created. Also create a new Armor Addon that points to the same mesh. Edit the name and stats as desired.
Create the Crafting and Tempering entries to go with it.
Done.
Aime's Defenders is a mod that does this for all the vanilla daggers, including a bound dagger spell. But if you want to create a custom defensive dagger (or any other weapon) from another mod, follow the steps above. I just did so with the
Elven Silver Dagger mod.