This is actually the plan. Not the least since I, the founder of the site, is a big Challenge collector myself. My goal is to be top 30 in the world. I have manually checked myself once or twice, don't remember my position though.
I'll look into creating this list later today. Shouldn't take more than an hour or so (hopefully).
And as have been stated in comments. Project-GC does distinguish real Challenges from others.