The Hassassin's Vestments Set features a Faceless hood for the unidentified Assassin (And a normal Hood.) As Well as Elite Hassassin's boots, robes and gloves. The whole set was the Dark brotherhood redguard Set which has been converted in Gimp and opened in photoshop to change some of the textures and colours.
To find the set Go to the inn located in riverwood and behind the counter beside a pillar is a chest containing all the Hassassin equipment.

I recommend using Jaysus swords for scimitars as they fit well with this set -http://skyrim.nexusmods.com/mods/1002/?
I also recommend downloading my follower mod to fit the Hassassin theme -
http://skyrim.nexusmods.com/mods/38262//?