I recently picked up the Jedi vs Sith Essential guide to the Force book, and it talks about several side traditions of force users mentioned in TSL, and I thought it might be interesting that besides their robes, bands, and gauntlets the party could pick up some of their weapons as well.
The easiest of the lot to make (I think) would be the Wan-shen used by the Matukai. It's a pole ax/spear type of weapon that a moder could likely build around the Force pike model. Wookiepedia's info on the weapon
The other one that could be interesting is the Diskblade used by the Zeison Sha. This one would have to be built from scratch. Wookiepedia info on Diskblades
The power of the Sith is to hide in plain sight, to corrupt unnoticed.
How the frak do you expect to go unnoticed with Sith tattoo all over your face?