Hm, it doesn't seem to be that common...but I remember strangeandcharm used to write things like that on LJ and now on DW. One I can particularly reccomend is 'the boy with the kaleidoscope eyes' http://strangenessandcharm.dreamwidth.org/86075.html. Not sure about the others but from a scan of the masterlist I think there'll be several there for you.

Strangenessandcharm (http://strangenessandcharm.dreamwidth.org/) on dreamwidth. Most of her stories are dean/cas focus and slash, but Sam is usually around and helping at least and some are very much the 3 of them.

Also misachan writes some lovely stories, and although again, there's a dean/cas focus to a lot of them they're a delight to read.

REB Jenn (http://www.fanfiction.net/u/1137666/) has written four non-slash stories that include the 'team' and are awesome cas whump stuff
Follow
Cut the Cord
Comfort to the Enemy
The Devil you Know

I've read some of Daylight's (http://www.fanfiction.net/u/52606/) and she's published some more recently that I haven't read yet.
My favourite of hers that I've read so far is 'A time for rest and a time for sleep'.

thanks for all the suggestions everyone :)