I'm not sure this is the story you are seeking but it's a beautifully written story in a similar vein:
My Life Closed Twice by Anaross Summary: Post-Not Fade Away. Buffy seeks Spike's remains, but then finds him in the most unusual place. Spike/Other, Spike/Buffy. Anaross says, "Not sure where this is going. But new fic. PWP--- Poetry without plot.
Well, no poetry yet."
Canon to...Post NFA