I remember finding a few years ago, an awesome rpg maker resource site.
It was in Japanese, and you could pick and choose what system you wanted to search for, what kind of resources, etc. and from there it listed all sites of people who had what you wanted there.
Check this list here, you might find it. http://forum.chaos-project.com/index.php/topic,1835.0.html
Mm, yes, some good stuff in there like loose leaf (which I plan to mirror sometime) but the one I'm talking about is not unfortunately.
I suppose you can say it is the same those fansearch sites, where people submit their site and describe it...