I feel you should warn people about the dangers of face pulls, as recommended in "Heal that Hunchback", for example. I added a few to the end of my workout yesterday, left my eyes wander, and smashed the metal part of the rope handles into my nose. Thanks for that. Unanimously voted "Tool of the Day" by the few souls actually working out at that time.
And now for your PR question - I'm going to pick up a PVC pipe as recommended in the above article. Does the length matter? As in, while applying the pressure on the spine, does the surrounding area take some of the pressure too?
Also, out of curiousity, you stated that some Japanese powerlifters were using a 6" diameter - why? Is this because their degree of thoracic flexion was so great that they can absorb smaller diameters? What are the benefits with the larger diameters?