I know this story!! It's something like Dawn gets a ring (or Halfrek over hears her during her birthday) and makes a wish in passing and it switches Buffy and Spikes roles. Buffy is British and lives in the crypt and Spike is Dawn's brother and the slayer. I feel like Spike finds Buffy at the bar at the Bronze surrounded by guys and he tries to intervene. She gets attacked by humans behind the Bronze and goes to Spike and Dawns house and Dawn lets her stay, kinda helps fix her up. Spike comes home (fuming?) and sees Buffy sleeping on the couch.
Is this ringing any bells? Am I thinking of the same story?
I feel like it was called something like Careful What you Wish for, or In Her Shoes or something like that. I thought maybe it was by Laniew, but she doesn't have much left of her stories since geocities went kaput.
UPDATE:
I think I found it. I was right with the title, wrong with the author. Is it:
Careful What You Wish For
Summary: Dawn makes a wish without knowing it will change the world she lives in. Buffy/Spike Romance
Spoilers: Season 6 – Post-"Wrecked"http://www.sinister-attraction.net/stories/s/carefulwhat.htm