I seem to remember you saying in one of the discussions you had with Steve Guttenberg about audio measurements that you don't like blind testing, but I still have to ask, have you tried doing double blind testing of the headphone cables to see if you can still make out any differences?
I know you've worked with NwAvGuy on your amp measurements, so I'm curious if you've read his blog posts on the subject of blind vs sighted testing, and what your current thoughts are about it. He seems to make a pretty bullet-proof argument that sighted testing of audio gear is extremely problematic because it's impossible to overcome placebo and confirmation bias if you know which product you're listening to, no matter how experienced a listener you are, and blind testing is the only way to reliably remove that as a factor. In one article he even demonstrates a situation that shows blind testing to be a better way of picking out subtle differences than sighted testing (listeners weren't able to tell the difference between two black boxes--one of which was a straight wire, and the other added distortion to the signal--until they did a blind A/B/X test, where the differences became obvious).