Not exactly what you requested...

Dubious Consent by PurpleMoon3.
Summary: Loki is tired. Gabriel is shopping for a new vessel. Thor always thought angels were just stories to scare little aesir into behaving.

http://www.fanfiction.net/s/8296781/1/Dubious-Consent

Thanks for the rec! I really liked it actually...all the angst!

Well, there is this little crackfic:
From Loki, With Love (http://www.fanfiction.net/s/8453431/1/From-Loki-With-Love) by Slinky-and-the-BloodyWands
Summary: Dean wakes up wearing a Captain America costume. If only this was the weirdest thing that had ever happened to him.

lol...this was brilliant! Thanks for the rec!

Not quite what you asked for, but the closest I can find: http://www.fanfiction.net/s/9507205/1/The-Last-Archangel

"Supernatural/Avengers fusion. No one knows where angels go when they die, not even the archangels. And if one finds himself in a different universe after death? It's one thing to leave heaven purposefully, it's another to find that heaven isn't even there. And Gabriel is alone."

Basically, Gabriel falls like Anna did, and gets reborn as Tony Stark. I haven't read it, so that's really all that I know about it.

Thanks for the rec!! I loved it! =)

http://archiveofourown.org/works/6070225/chapters/13913380
Revitalized in Frost's Embrace;
"After Gabriel’s brother killed him, he thought it was over for good. Turns out, even angles get second chances. Given a new family, Gabriel is determined to cherish them. Even if they come with a few kinks; but it’s nothing a little Trickster magic can’t fix, and life is looking good. Until he discovers something from his old universe may have followed him home."

It's really interesting and I can't stop reading it. You can find it of FF.net too, if you prefer.