Will women ever best men in ultra-distance running?
 

Doubt it, but maybe in ultra marathons and the like, but not in anthing shorter than 50 miles.

There was a woman a few years back that won the Badwater run a couple of times.

I seem to recall reading that women hold all the world long distance open water swim records. Something about their higher percentage of body fat allowing them to tolerate the cold and fatigue longer. I probably can't produce a link though.