(#) Guess 2013-03-24
The story you want is Odd Ideas by Rorschach's Blot Chapter 112 Handcuffular one of the Omake down at the bottom called Rivals.
Anyways, so far your story is pretty good. I can't wait until its Snape's turn for an unfortunate accident.
Author's response
Thanks, but I already knew it. I published this story over on FFN last summer and got a response (from Rorschach's Blot himself) about where I'd seen it. My mistake, not tweaking the author's note.
And, yes, something bad will happen to Snape, by and by.