You can get a 0X naginata in the backroom of the weapon shop in the Landing. As far as I know, the only way to get a vultite nagainata is from the erithi weapon smith who also makes the vultita katanas. Now, we tried to enchant a naginata just now, and the potion just rolled off. Looks like the weaponsmith has paid someone off so as to be able to keep his monoploy on magical naignatas.