I know a few people who have been suffering with the above ailments. A bit of advice I got from a trusted source at the weekend is try to move your cleats either 3mm forward or backward. Basically try it out and you should be able to eliminate a lot of the numbness.
In regards to cramping apparently drinking Indian Tonic Water, not loads of it but a half bottle a day around the time you are going to be doing a big event or race etc should help as it has quinen in it.
Cheers
Marek...