Well, I've finally got the chance to read this, and I am positively charmed! Young Severus is a wonderful influence on Harry, and the idea that it was the Unspeakables who made Tom Riddle into who he was is just chilling.
And, this story being what it was, I can easily see how shoehorning smut into it would have been a challenge, so don't worry on that account -- I love it anyhow!
Thanks for writing it, and thanks even more for posting it!