That's a great idea! I know Fanlore has a doujinshi documenting initiative (see: http://fanlore.dreamwidth.org/48395.html), but it's far from a comprehensive resource. Still, an option to consider!

I used to get all of my Hikago doujinshi scans from igo_yaoi back in the day but I don't think there've been much scans posted there for a while now.