Not that I'm obsessing -
Another series you didn't mention but you implied you were open to others --

Smoke on the Water by ratherastory for claudiapriscus
Supernatural, Burn Notice
General AudiencesNo Archive Warnings ApplyGenComplete Work1 Sep 2010

http://archiveofourown.org/works/210038
http://www.fanfiction.net/s/6293145/1/Smoke_on_the_Water as mousme id: 6293145

Also, this link to a previous request (comments one and three) have some good Harry Potter crossovers -

http://spnstoryfinders.livejournal.com/7446616.html#comments

And concerning a rec made above, under NCIS, Way to Kill by maras_morgue - as far as I can tell it is WIP since 2008 and the author's journal is gone -- the links aren't internal to the story but I'm not sure I can post 11 active links -- so if you go to the crossover community listed in the post above [ http://sn-crossovers.livejournal.com ], hit the tag for NCIS and then go back 50 posts (5 pages) you'll be at the start of the story - she posted almost entirely in February and March of 2008 but stopped after part 11, although it was still marked tbc. If someone else knows differently, feel free to share.

And here's another place to look - an archive (supernaturally twisted) http://www.spntwisted.com/