I had this too years ago when I first took up running - it got so bad my knees became painful as I ran with little feeling in my feet. I tried the bigger shoes, arch supports, etc but eventually gave up.
I went back to running just before Christmas - I still get it occasionally - it's worse if my calves are tight from a previous run - at the first sign, wiggling my toes does sometimes help.
ANYWAY, I saw an article recently in RW about exertional compartment syndrome - muscles fill with blood tightening the muscle covering which puts pressure on nerves within the muscle compartments - this all makes sense but I can't believe doctors/physios haven't sussed this out when confronted with such symptons??