Is there any mod on Skyrim out there which....

I've forgotten how to do a clicky http://www.nexusmods.com/skyrim/mods/20372/?

Schlongs of Skyrim

There are, but they are very buggy, as changing the weapon from 2h to 1h isn't just a matter of changing a flag. The mesh of each item and the reference points on the mesh are set up uniquely for it's animation type. This makes some animations weird and messes with the sheathing of the weapons.

Check here.