I had toe numbness after just 6 miles. Got rid of the Sidis which were both too narrow and too long. Added orthotics to my shoes. Numbness gone, now the outside of my feet start to hurt around 10-12 miles. Sometimes you just can't win. It's not unbearable but distracting and annoying.

Numb toes could be a sign of compression of the metatarsal bones(the ball of your foot). While they make pads specifically for this, you'll spend a lot of time finding the right size, shape, and correct placement of the pads. You can try them on the cheap, though. Also cheap are the moldable insoles sold at the drugstore. If they don't work I'd see the podiatrist. Nerve damage is a bad thing.