mmm, Sam/Priestly makes me happy. And Sam/Gabriel is my OTP. So let's see if I can help you out.

Coffee For Broken Hearts (http://gentlezombie.livejournal.com/5982.html)
Summary: Written for thespnkink_meme prompt: Priestly/Sam comfort-sex. Dean's in hell, and Sam's on a downward slide. Sam walks into a sandwich shop with three dollars and twenty-five cents. The guy behind the counter is really nice though, even when Sam falls asleep in the corner booth because he's been grinding himself into the dirt.

You & Me Verse (http://somethingfunny.zxq.net/youmeus.html)
Summary: Sam loves Priestly, Priestly loves Sam and Dean is very annoying brother.

Subtle Reminders (http://white-monarch.livejournal.com/11153.html)
Summary: Sam meets Priestly while he is away at collage. A whirlwind romance almost takes Sam away from Jess. Years later an old flame is rekindled.

Life and Love at the Beach City Grill (http://shadowglove88.livejournal.com/73075.html)
Summary: When Sam goes to Stanford he discovers Beach City Grill and meets Priestly through his friend Jess, and he immediately finds himself captivated by the kilt-wearing, blue haired 'mohawk guy'.

The End of Heartache (http://somethingfunny.zxq.net/endof.html)
Summary: Priestly sees Beautiful Stranger at the bar


As far as epic long Sam/Gabriel... I'm not sure. I do have some that are long-ish?

Wordcount: ~81k
The Trickster Saga (http://moorishflower.livejournal.com/113985.html)

Wordcount: I don't know, but it's LONG and INTERESTING and AWESOME.
(College AU)
Cold Academic Hell 'Verse (http://moorishflower.livejournal.com/179572.html)

Wordcount: ~50k
Dies Irae, or Something (http://alchemyalice.livejournal.com/5255.html)
Summary: It starts with headaches, and it ends in a clusterfuck. So, business as usual, Apocalypse-wise.

Wordcount: ~47k
(Highschool/College AU.)
Starting From Zero, Got Nothing to Lose (http://softshinythings.livejournal.com/549.html)
Summary: When John insisted that Dean was to attend college, Dean drove halfway across the country with his best friend Cas in tow. But when Sam finds that he can’t handle the way John is without his eldest around, he finds solace in Cas’ brother, who doesn’t ask questions but always offers an escape route.

The links to the other chapters can be found under Fast Car 'Verse (http://softshinythings.livejournal.com/5393.html) in their fic Masterpost.

Wordcount: ~39k
Honestly, I never finished this one. But that isn't because it wasn't good. The author had gone back to make revisions and I just never got around to reading the finished product. But I liked what I read of it before then.
Blood, Feathers, and Ashes (http://ihasstopwatch.livejournal.com/166532.html)
Summary: Their list of allies is growing thin, stretched almost to its limits. With the final battle between Michael and Lucifer looming over them, Sam and Dean are forced to fall back on their last resort plan - calling on magic so ancient and powerful that even Gabriel is uncomfortable with it.

Wordcount: ~31k
Your Bottle Is Empty (But Your Glass Has Been Filled) (http://archiveofourown.org/works/73779?view_adult=true)
Summary: "Becky wants me to tell you that she's read everything so far and that she...thinks the romance plot is very compelling."

Word Count: ~27k
Where the Ladder Starts (http://moorishflower.livejournal.com/150013.html)
Summary: After losing his fiancee in a fire, Sam Winchester packs up everything he needs, sells everything he doesn't, and moves from sunny Stanford to loud and muggy Philadelphia, where he uses what little money he has left to open a bookstore. There he meets Becky Rosen, fan of the popular Supernatural comic series and aspiring writer, and the two become good, if unlikely, friends. But as Becky begins to write her first ever fantasy romance novel, Sam's life takes a turn for the fictional when he finds an amnesiac man in an alley near his store.

Wordcount: ~25k
This one wasn't one of my favorites, if only because of the "slight dub-con". But it's a really good fic.
Borrowed Heaven (http://community.livejournal.com/miyawriting/17714.html#cutid1)
Summary: AU. In a world where angels are running the show, the Winchester brothers investigate paranormal cases for the Hunters Department. But Dean is ill and Sam has to take a job at Club Rouge as a "host" to pay the new bills. He certainly wasn't expecting to catch the eye of an archangel. As he and Gabriel get closer, Sam also takes on a case that will prove far more complicated than anything he would have imagined.

Wordcount: ~23k
This one was cute, I think
Of Freaks and Britney Spears (http://pylarwoman.livejournal.com/78999.html)
Summary: In which Sam's in love with Castiel and Gabriel has a brilliant plan to get them together.

lol i just realized u made 2 different comments lol. But yes Thank you and I just watch a Sam/Priestly themed AMV on Youtube and got me thinking u know. Anything over 20,000 is EPIC enough for me :P :)Thank You!

Scrolls down list *dies

WHOA! YES! THANK YOU! :D

Dean/Cas

The Voice of the Turtledove (http://obstinatrix.livejournal.com/41668.html)!! by obstinatrix
Summary: Castiel was eleven years old when he first felt there was something wrong with him. He's twenty-nine, a Roman Catholic priest in a small New England village, before Dean Winchester shows him that there isn't. AU.
- I've ben rec-ing this since I read this! Lovely, lovely story.

There's Only One Sure Thing That I Know (http://blinkiesays.livejournal.com/143374.html) by blinkiesays
Summary: Dean doesn't even get halfway through explaining before Bobby starts laughing. When he lets himself think about it for more than five seconds, Dean can almost see Bobby's point: he's faced down demons, witches, vampires, werewolves, ghosts, angels, and Satan himself and now he's been defeated by the God damn Midwest.
- Best domestic fic I've ever read!

The Fourth Wall (http://community.livejournal.com/libraryofsol/106018.html#cutid1) by Libraryofsol (http://community.livejournal.com/libraryofsol)
- Dean/Cas, Sam/Lucifer, however.

Blessed is his Child (http://community.livejournal.com/ameonna1_writes/7198.html#cutid1) by Ameonna1_writes (http://community.livejournal.com/ameonna1_writes)
- Still a WIP, sadly. But very very interesting read, it'll get you hook in no time.

this is Kelssupe who is too lazy To sign in at the moment BUT THANK YOU SO MUCH :D

For Sam/Gabriel and Dean/Castiel, I recommend all fics by entangled_now (found here: http://community.livejournal.com/libraryofsol). She also writes a lot of other pairings. :)

softshinythings has a lovely AU with Sam/Gabriel and Dean/Castiel: http://softshinythings.livejournal.com/5393.html#cutid1 (link to masterlist, but the fic is the Fast Car 'Verse).

moorishflower also writes Dean/Castiel and Sam/Gabriel, but the biggest must-read (in my opinion) is her Cold Academic Hell AU 'Verse. A-Sides are Dean/Castiel, with the B-Sides Sam/Gabriel: http://moorishflower.livejournal.com/179572.html

moorishflower's Delicious masterlist: http://www.delicious.com/moorishflowerfic