my solution to numb feet and long distances is to wear mtb cleats which are level with the sole and can be walked in easily. I ride with double sided pedals with the cleat clip on one side and a plain pedal surgace with friction teeth on the other side. If I am cruising at a steady pace for distance than I unclick so that I can flip the pedal and move my feet around. Also I find that the shimano mtb shoes have a firmer sole and roomier toes, so between being able to move my feet around to vary the pressur points and an easy fit on toes in my socks and shoes, I have pretty much eliminated the problem. It's like having aerobars so that I can move my hands.
marni
Katy, Texas
Trek Madone 6.5- "Red"
Trek Pilot 5.2- " Bebe"
"easily outrun by a chihuahua."