numb toes are usually because of the location of the pedal in relation to the nerves in the your foot. Two things: first, try moving your cleat back a bit. In most cases this will solve the problem. The other possibility is your shoes. In either case, talk to your LBS and get their imput. You've dealt successfully with all the other bike/body interface areas, but shoe/pedal interface problems are often overlooked and assumed by the sufferer to just be part of the deal...kind of like skiboots and iceskates not all too long ago.