Have a list that you would like to promote? Came across that great list that you just have to share with everyone? Here's the place to post it, and I'll update this thread with a growing list.
Hanzo the Razor is, as ptero said, a must for this list.
I also recommend the documentary about Bob Flanagan called Sick.
I haven't seen it, but the documentary Modify might be appropriate.
(edit: Whoops. Sorry; you have both of these listed already.)
I once saw a film from the Philippines which showed detailed footage of a "coming-of-age" tribal ceremony in which young boys were circumcised with stone implements. If I'm remembering correctly it is either Perfumed Nightmare, or by the same filmmaker. It is not available on Netflix.
You might also want to keep an eye out for the films of Charles Gatewood.