It's not quite reincarnation, more a take on Quantum Leap, but Change My Life Again by Eugara on AO3 has the boys from Season 8 jumping into different bodies and placed into unusual circumstances.

Thank you!

Lee Marie Jack at FF has several stories with that theme: https://www.fanfiction.net/u/2789168/LeeMarieJack

My epic serial also has eastern mysticism as an underlying theme but it'll be a while before it focuses on reincarnation head on. There'll be hints of it in the upcoming episode, though: http://fanspired.livejournal.com/1394.html

Thanks!

If you don't mind a self-rec, this fic (http://amypond45.livejournal.com/30329.html) suggests future reincarnation :)

Ooh, thank you!

Darkness on the Edge of Town by epeeblade meets your request. I loved this fic!

http://archiveofourown.org/works/12743

Yeah, I've actually read this before. But thanks :)

This was a good read.

So this one is definitely reincarnation, very haunting and well done. It sticks with you. Not wincest though. Sam is now the older one, and remembers the first time around.

http://honeylocusttree.livejournal.com/71026.html

Thanks! I'll give it a go

Another self-rec for you - this is Sam and Dean reincarnated as J2!

http://annie-46fic.livejournal.com/55118.html

As Through a Glass and Darkly (http://archiveofourown.org/works/524025/chapters/927238) by lexicale: "Everything is the same, except for how it's different. Sam and Dean grow up with two mysterious guardians, a demon and an angel respectively, living in their shadows and preternaturally bound to them. They still move all around the country, saving people, hunting things. There's still an acceptance letter to Stanford and a family full of pain and anger. There's still an unbreakable bond of love and desperation between two brothers -- and there's still a man with yellow eyes with secrets enough to shatter the world. A re-write of Supernatural with Hindu mythology as its basis instead of Christian mythology."

If I remember correctly, the reincarnation in Non Timebo Mala (http://archiveofourown.org/works/273894/chapters/433454) is more suggested than explicitly stated, but it's still a great story: "This is my very AU version of the Colt's making. It's completely a child of my wild imaginings, thus expect anachronisms, improbable situations, and flagrant display of personal fanon. This can be seen as an alternate universe, or an alternate timeline."

I'm not sure it's what your looking for, it's a crossover. " Puddle Jumping" by calamityjim http://calamityjim.livejournal.com/800.html
Gabriel, in a solution to stopping the apocalypse, tears Sams soul loose and sends it adrift in the multi verse to be reborn again, and again, Dean begs to join him an Gabriel grants his wish. I can't remember if it is any actual wincest in it, what I remember most is the desperate love they have for each other, but I can't recall if turns into wincest, when I read it it was still an WIP.

There's also rei-c's Vernacular Process, where a Civil War-era couple is reincarnated into Sam and Dean.

https://docs.google.com/document/pub?id=1uLGHduNXKu-nA47MuQR9HcC1xWoWaWUWbTqfk7MB5Ik

If you're still looking for fics like this, "Under Falling Leaves" by germanjj (http://germanjj.livejournal.com/67902.html) is amazing!

General gist is that Dean and Sam are reincarnated as Jensen and Jared, Jared remembers and Jensen doesn't... at first, anyways. It's one of my top 5 favorite fics of all time, so I can guarantee that the quality is there. :)