I'm certainly willing to help out. I was just over at the ds_c6d chat and several of us were quite excited over the idea of a dS/SPN crossover! In fact a few of us might have *cough* role played it for about half an hour.

dS is a huge, huge fandom, so I can't imagine you'd ever run into anyone who hasn't heard of it. LOL! Anyone who is anybody has writen dS, it seems, and OMG there are already hundreds of dS fic up at the AO3. Have you dropped by ds_noticeboard or the Crack Van's dS tag (http://community.livejournal.com/crack_van/tag/due+south)? Due South Seekrit Santa is set to go live in a few days, too. I mean if you know all this, ignore me, I'm just pimping! :) But aside from the whole Ray Wars (which don't let anyone fool you, are still sometimes fought) the fandom is lively and enormous. It's a beautiful thing.