Whoa shit, I have this photo saved on my PC since forever http://i51.tinypic.com/1z19vn6.jpg

Seems to be the obvious reference to this drawing here.
Also if anyone could prove the source for it I'd much appreciate.

HakureiSM, you are right.
In the commentary, the artist declared this pic is a derivative work based on a photo.
It is interesting that most of commentators on Pixiv have the same photo.

I see.

I really wish I could find the source for that image, who's the model, etc.
I got it off 4chan several years ago, so I don't even have any means to start.