I think Chash's Happy Ending could fit the bill, in the off chance you haven't read it. Coda to 4x18, not about fans or fandom but fanfic. (There is also that crazy verse of hers where Castiel writes fanfic, but I feel that isn't exactly what you're looking for here.)

I'll check it out - thanks!

Hmmm, do you have the fics where Sam and Dean watch Jared and Jensen's movies? If you do, I'm too lazy to look for them. If you don't, I'll hunt.

I think I kinda now one, It includes the 4 guys in it, hot and steamy sex in all kinda pairings , foursome include! and it also had a great plot, from season 1 to 3 I think, here is the link to the master post, http://blynnk.livejournal.com/tag/looking+glass!verse+master+post, hope you enjoy it!!

Well, the guys don't meet in the ones I was talking about. But I looked them up since I was thinking about it again!

Celebrity Sighting (http://nevcolleil.livejournal.com/133247.html) (Sam/Dean, 400 words, PG-13) and its sequel Cry Wolf (http://nevcolleil.livejournal.com/133515.html) (Sam/Dean, 400 words, NC-17) by nevcolleil

HOWEVER. I just clicked the link and they're dead. Very, very, verrrry sad.

LOL sorry I think I made a rec of something you weren't looking for lol, but I highly recommended!