This hue has been an obsession of mine for roughly 10 years so I will share my opinion and knowledge.
Of the old school items the robe from the mage and the leprechaun boots from around the same era were the only non-crafted wearable items of that hue.
I had 2 pieces of authentic evil mage cloth and they stacked with the thrasher cloth.
The tokuno pigment shadow dancer black is the same hue.
The robes themselves (the double-blessed ones) that still survive are ridiculously rare, indeed I've been trying to purchase one for several years with absolutely no luck. The only people I know of that own them are Vladimir and Oblivion on Atlantic, and Oblivion's is no doubt tainted by the blood of innocents.
To the OP, I have quite a bit of the cloth, send me a PM.