There are at least two Dean/Misha fics I can think of, both are French Mistake codas, but neither of them ends with Dean/Misha staying together or even wanting to stay together. Both are well-written, though.


1. Imitating Life (http://littlehollyleaf.livejournal.com/436038.html) by littlehollyleaf, NC-17

Summary: Set in The French Mistake universe. To safeguard the angelic weapons he stole from Heaven, Balthazar has entrusted the keys to their hiding place to Sam and Dean and sent them into an alternative dimension. Unfortunately, Heavenly hitman Virgil followed them through and managed to swipe the keys during the ensuing confrontation. Now, the brothers need to find Virgil stat or their world is headed for a meltdown when he hands the keys over to Raphael who plans to use the weapons to re-start Armageddon. The problem is - how? Because if tracking down Virgil isn't hard enough they also have to keep up the pretence of being a couple of crappy TV stars, investigate the mysterious arrival of one Richard Speight Jr. and deal with a clingy Castiel-lookalike who can't seem to stop fawning over Dean.


2. Not In Kansas (http://archiveofourown.org/series/16277) series by MollyC (http://archiveofourown.org/users/MollyC/pseuds/MollyC), I think it's NC-17, too

Summary for the first fic in the series: "Remember how I said J2 got me good yesterday? Yeah, that was maybe less of a joke than I originally thought."

That was me, didn't mean to leave anon comments.

AO3 does have a Misha/Dean tag (http://archiveofourown.org/tags/Misha%20Collins*s*Dean%20Winchester/works); there are...13 fics. Not a lot, in the whole universe of fic, but enough to keep you busy for a day or two. :) (Almost all of them are based on the French Mistake, of course.)

Here are two I've found:

This one is pretty short: untitled french mistake (http://floatxxaway.livejournal.com/6918.html) by floatxxaway and was originally posted in deancaskink.
"Misha can tell this isn't his boyfriend. But does it stop him from fucking him? Of course not."

And I haven't read this one yet, and the Misha/Dean is more implied, according to the pairings list: The Other French Mistake (http://lizzstomania.livejournal.com/6519.html) by lizzstomania.
While Sam and Dean were in an alpaca-ridden alternate universe, what happened to the 'real' Jared and Jensen? And then Dean and Cas get it on after Dean comes back.