Shadow Hunter Vayne Skin
I plan on drawing the concept art soon, but here's a description of it. Also I draw some inspiration from the Nightingales in Skyrim.
The outfit would be black and gray, with a long cape and a hood. The difference between this and the Nightingale armor would be no mask on Vayne.
The best part is when Shadow Hunter Vayne uses her ult and tumbles to invis, there would be a shadowy particle effect when she goes invisible, and then when she comes out of invis as well.
Again I plan on drawing concept art of this, but if you want a good idea of what it looks like, just google image Nightingale Skyrim, there wont be a mask though on Vayne.