I think this is a decent idea for some throwing weapons. Of the ones that aren't currently shown: axes and hammers could be easily located on the hip, throwing lances could be put on the back. Throwing star and throwing knife type weapons could show up as a bag or sheath on the hip, but these models would have to be created.
For all of the above however, they still might not display if the player has another item that is equipped in the same location. As there are so many one-handed thrower hybrids, it would be important to make sure that the throwing weapons store on the hip opposite the sheathed one-handed weapons.
