There is a short crossover where a phantom truck is chasing Jim and Blair, and Sam and Dean save them and Jim can see their spirit guides, but I can't find it for the life of me.

The only other one I can think of is Boundaries of Self (http://frayen.livejournal.com/209690.html) by Selena, but it is unfinished. I also think I have some unfinished snippets lurking on my computer that I wrote ages ago, but they may have been lost when my laptop crashed. Wish I could be more helpful. I was hoping other people would respond to your request since I would love to see more crossovers between these 'verses.