Well... Kinda. I know how to do the glitch but I really don't know what triggers it so I can control it rather than having a random item duplicated...
But I guess I should explain the glitch firstly.
~Requirements~
A follower
Hearthfire home with basemant*
Handful of items you want duplicated (You need a good handful too. This doesn't work on single alone items).
Note*: So far, it seems it only works with Hearthfire homes. I hadn't seen this working with other homes/areas quite yet.
~Steps~
1: Get a stolen tag on the items you want duplicated. Best way being putting them in a barrel in your home and telling your follower to "Take All". (Note: the tag will be removed later on).
2: Drop every item onto the ground in the basemant of your home. (Don't pick them up as they count as stealing).
3: Tell your follower to pick each individual item back up.
4: Once your follower picked them all up, go straight upstairs and back downstairs...
5: Upon going back downstairs, one or more items you have dropped will "respawn" (FYI: duplicate) and are take-able (Not steal-able). You can also get your items back from your follower and they will no longer have the stolen tag...
And that's it. So far this works pretty much on any object. Originally, I was trying to remove some stolen tags after moving into a Hearthfire house and doing this in the basemant of my new home... And well a few items respawn when doing the 2nd inventory of my items. (Including Konahrik's Mask, Dawnbreaker, etc).
Also. http://i.imgur.com/FKmlfnE.jpg (Accidentally duplicated Chillrend when trying to duplicate Auriel's Shield. Wanted two of that shield on my main. One for myself and one for my follower).
And ye'h. What I need help with is figuring out what triggers a specific item to duplicate rather than a random chance, basically! Any ideas?
~Edit~
Forgot to say... On the Xbox 360 with all patches and DLCs.