My female mage has modeled a variety of clothes items trying to fit the look of the Telvanni robes and the one thing that goes perfectly is the
Morag Tong boots and gauntlets. The darker chitin look matches the shoulder pads visible on the robes and they don't clip through the robes like some other clothing items I tried. I reckon the copper and onyx circlet would fit well, too but my mage is running without any sort of helm right now.
Sorry if this is obvious but it took me a while to get the right look and just thought I'd share, it being the season of good will and all. Merry Xmas!