My favorite, don't know if its "extreme" enough for you but too each his own.
Taylor Hill Throat Gaggers 4
http://qmov.com/sexy-brunette-gagging-and-choking-on-cock?wm=
Full 13 min vid can be seen at x v i d e o s
rrggghhh its one of those .rar vids ... how do you see those?
Melanie Jagger
She seems to like it ok, but she does choke alittle in each vid
Vid #4
http://www.dirtboxbitches.net/creamfilled/9_12_05/melaniej_b.html
Vid #3 at the end
http://www.ickysticky.net/assplundering/gallery26melaniejagger/index112.html