You can rent a set of any of these items for 60 days with a Returned Milletian Return Coupon (or something along those lines), which you receive at some point during the returning questline. You can also purchase any of them for 18 Returned Milletian Seals. I've posted a picture of the available weapons to purchase too, I'm not sure if these are new/limited, if you'd like detailed pictures of each one just let me know. :)
The detailed pictures of each one are in this imgur album, for the interested.