Just a thought from my hiking days- we would wear two pairs of socks. A thin polypropelene one inside a thicker wool sock. Friction is dissipated between the two layers. But this would probably not fit inside your current shoes.
I just read about this book in "Her Sport + Fitness" magazine (which I love by the way):
Fixing Your Feet
by John Vonhof
Edited by Wilderness Press (http://www.wildernesspress.com)
$18.95
It's supposed to have a chapter on "175 ways to prevent blisters"...
It might have one for you!!!![]()