Better question is, why would anyone need something like that if you are capable of modding your characters stats? but as far as i know, every item can have 3 sockets, amulets and rings are an exception and can hold 3 legendary gems, just add all of one stat to the amulet, then add all of another stat to 1 gem and so on.
amulet = 6 x whatever stat and 1 x 3 sockets (add all Vit if ya want)
gem 1 = 6 x int 1 x vit,
gem 2 = 6 x dex 1 x vit
gem 3 = 6 x str 1 x vit
6 x 1465 = 8790 and 4 x 1465 = 5860... tada