Relatively recently someone had searched for a story in which Sam was kind of obsessed with Dean. It was a Djinn fic where Sam was hit by the Djinn [sorry, I can't find that particular entry].
The story was Better Elsewhere by Veronamay
http://archiveofourown.org/works/1190469/chapters/2429007 It's a fun read. But I kind of crave something different now because of it.
In the fic "real world" Sam was in love with "real world" Dean but Dean was in denial. Then Sam got hit by the Djinn.
In the Djinn world, Djinn-world!Sam had a bit of a psychotic break due to his obsession with Dean and was placed in an institution. The story followed Djinn-world!Dean who eventually returns Sam's affections.
I'd love to know if there are fic in which Sam is obsessed with Dean, but Dean DOES NOT return Sam's infatuation. He loves Sam, but only in terms of brothers. Like, Sam might be even kind of creepy and Dean has to try to instill hard-line boundaries to stop Sam from just kind of consuming him. Or Dean makes sure to not be totally alone with Sam because Sam is mostly fine/normal...but that can't always be trusted.
Or Sam is constantly pushing boundaries, Dean continues to love him platonicly and tries to cope.
I'm fine with rape, assault, dub-con, just pushing Dean till he has to push back, or being creepy and suggestive without anything more happening.