I'm pretty sure this fic - Divination of the Heart by mznaughty01 - fits your request : http://mznaughty01.livejournal.com/6223.html

xx

Thank you! :)

virtualpersonal's Purrfect Mate (http://virtualpersonal.livejournal.com/236282.html)

Summary: Photographer Sam Wesson has made it his life's work to take pictures of 'the unexplained.' Only now, back from a trip to the jungles of the Amazon, he is one of the unexplained - a werepanther. Deciding it changes nothing, he is on the prowl in the nightclubs of miami, searching for the the thing that is selecting and killing young people from the clubs. Dean Winchester is hunting that same creature and runs into Sam, a lot. The heat between them is incredible but is that enough to prevent the hunter from hunting that which is not human?

Thanks :)

I've got a couple:

Eat You Alive (http://archiveofourown.org/works/875793/chapters/1683454) by thecapn: "Jensen is a werewolf. Jared is the boy who sits next to him in English class."

Kant's Dove (http://tryfanstone.co.uk/kantsdove.htm) by jaytryfanstone is an awesome story in which Sam is an angel and Dean is a prostitute. Sort of. They're both mostly aware of the situation, though. "In a dystopian paradise angel Inquisitor Samuel and rogue human Dean are uneasy allies. Together, they could knock their world from its foundations, but both of them have secrets to keep."

In Courting Death (http://archiveofourown.org/works/875482/chapters/1682682) by the problematique, Dean is Sam's reaper (again, not a secret though): "Sam Winchester lived the first six months of his life in a happy family; the next twelve years as John Winchester's only son, and the last decade as an orphan. He's supposed to die at twenty-two trying to save the woman he loves from a fire, because he doesn't have a brother to pull him back. But the night Sam meets his Reaper he discovers that Death is overly fond of pop-culture references, too beautiful to be real, and reluctant to kill him."

And then there's the Semiatuomagic Verse (http://archiveofourown.org/series/4154) by cala, in which Jensen is a wizard, Jared is something spoilery (and mysterious to Jensen), and then there's a side-pairing that matches your request perfectly.

Oh, I've already read Kant's Dove and Courting Death. Thanks for the other one though :)

This is a self-rec and I'm not sure if this is what you're looking for ...
Wrapped in Honey (http://lady-emebalia.livejournal.com/19053.html)
Summary: AU in which Sam is a monster who wants to buy himself somebody to feed on. Lucky him, Dean's on sale.

I didn't recommend this myself because I'm not sure it fits the description since Dean isn't unaware, but I have to say, I LOVE your story and am always happy to see an update notice in my mailbox. The power and who's-in-control dynamic you set up between the two of them is really awesome!

Thank you.

You're right, it isn't what I was looking for, but oh my god, it's perfect! I just literally spent my whole afternoon reading all 47 chapters and I am now eagerly waiting to read the rest of them! Thanks so much! :)

Yeah, I thought it was a stretch but it looks like it was worth a try ;)
I'll post the last two chapters next week, just be patient.
Thank you.

Have you read any of these?

* Bread and Blood (http://archiveofourown.org/series/179384): Jensen is a nice guy. He's kind and attentive, and there's a room in his apartment for his cats and bunnies he's occasionally feeding from. He works as a hooker for Frederic Lehne though he's badass when it comes to defending his ass against sleazy clients. That's one of the secrets he wants to tell his boyfriend Jared but he never has occasion to do it before he gets seriously hurt. A furious Jensen - even when naked - is something you better don't want to witness. // A little wooden toy cowboy is all Jared has left from his family. He falls for Jensen head over heels and even comes to terms with him working the streets - it makes for the best blow jobs, after all. Unfortunately, he will not get to know his other, bigger secret in this story - being shot at and lying in a coma is pretty obstructive.

* Total Eclipse 'verse (http://archiveofourown.org/series/217118): Jensen never knew that his whole life would change the day he met Jared Padalecki and nothing could have prepared him for it. Jared, on the other hand, knows exactly what he wants, and from the moment they meet, he wants Jensen. He knows that his life is nothing like his mate’s, but he’s willing to be patient and wait for Jensen. It won’t be easy, but it’ll certainly be worth it.

* Black Cat (http://archiveofourown.org/works/660480): Sam is a hunter with a secret he can't risk anyone finding out, not even the grizzled old hunter who doesn't know he has a son. But even though he knows better, why does Dean Winchester make him want to talk?

* Blood Moon (http://tryfanstone.co.uk/bloodmoon.htm): Sam is on the trail of Dean Winchester, the hunter who murdered his friend Kyle. Except Dean didn't kill him, and that's not the only thing that's not the way it appeared to be.

* The Beasts Inside (http://archiveofourown.org/works/697570): When baby Sam drank the demon blood, an incubus stole inside, preventing Sam's dark destiny but also starting a twisted relationship with his brother. Dean doesn't suspect anything is wrong... until he comes home changed. Then everything changes.

* Fishsticks (http://archiveofourown.org/works/952740): Castiel is a marine biologist that reluctantly joins his brother in a search for a mysterious underwater creature. Illustrated. (WIP, but already quite long and GLORIOUS)

* Polarity (http://virtualpersonal.livejournal.com/288223.html): Sam’s dreams of going to college and living a normal life are coming true and things couldn’t be more perfect, until he’s stuck with a roommate who hates his guts and does everything in his power to get rid of him. Castiel would like nothing better than to make friends and be normal. Only he’s not. He’s got these freaky wings that have matured to the point he can no longer saw them off, he’s got to bind them all day and wear a stupid trench coat, and now, he’s been landed with a roommate and is forced to hide his deformity twenty four hours a day. Something has to give and it's not going to be him.

* Our Story Is Infinite (http://storiesimakeup.livejournal.com/39585.html): Sometimes eternal love begins with hate at first sight. Jared's certainly did.

* Cupid 97 (This Ain't Your Hallmark Cupid) (http://aeroport-art.livejournal.com/33788.html): Everybody's got a love/hate relationship with their jobs. But for Jensen Ackles, top Cupid in the nation, after a hit goes wrong it's just a long, downhill slide from there.

And this one is kind of the reverse (Dean befriends a dog that's not just a dog), but I liked it a lot:

* Instinct (http://archiveofourown.org/works/1014391): When Dean and Bobby investigate a demon's house, they find an abused dog that is a lot more than he appears to be.

No, I actually haven't, except for 'Polarity' and 'Cupid 97'. Thank you! ^_^

You might try Becomes a Monster (http://runedgirl.livejournal.com/63320.html) by runedgirl or Honey and Flies (http://archiveofourown.org/works/336114?view_adult=true) by glasslogic. There's also Semper Familia (http://archiveofourown.org/works/696882?view_full_work=true) by Katzen and the Angelwings (http://archiveofourown.org/series/6229) series by leonidaslion.

Yup, I've already read the Angelwings series and Honey and Flies. Thanks for the others though :)