As the title says, i've the knowledge of two working dupe methods.
I'm ONLY selling these to a maximum of 3 people each, in order for it not to go "too" public.
Method 1:
Involves a vendorable item + the skills to communicate.
Method 2:
Usable with any item + a bit of luck.
PM me if you're interested.
Now, i have using method 1, succesfully gathered, for the FL legendary staff 25 Essence, in just one day, starting with 5.
These do still work and i've used this to dupe a few mounts now.