Hah hah, Dakota Jones' report of his victory over "captain ski-mo" is pretty funny and well-written too: http://blog.montrail.com/2012/05/a-race-report-of-much-depth-and-consideration/
On a much less grander scale, I'll report on the 2012 Grandeur "Fun" Run. This year I went 1:51:30 for "5th place"--do you get a "place" in a "fun" run? Based on the ~50 miles I've run this year, and if anyone is wondering or cares if skiing fitness translates to running fitness, I think I'm a good test subject.
Aerobically, I'd say there is a direct correlation. Aerobic fitness=aerobic fitness. And in any endurance event, that is a big component.
Movement-wise and muscularly, I think there is some correlation. The upward, quad-intensive, movement is very similar. For example, the first 2.2 miles of the Grandeur "Fun" Run climbs 3,300 vertical feet. Granted, that is not typical profile for a running race. But that particular profile is essentially the profile of any rando race or a typical skinner in the Wasatch.
However, running is different in that it requires much more use of calf and foot muscles. The limiting factor on the steep uphills for me were my calves. Poles helped, but my calves were on fire for the whole uphill, and later in the race, they cramped. With skiing, we use heel risers, and don't work our calf muscles in the way running does. (Maybe we should start skiing without heel risers?) In addition, running is different in that it demands eccentric motion from the quads. Skiing certainly strengthens the quads, but nothing can prepare the body for running downhill, other than running downhill.
One other aspect of running that I felt my body lacked was the ability to quickly and smoothly turn my feet over on the flats. My cadence was slow. But no surprise since skinning is a much slower exercise. I felt boggy through 2.5 mile flat section and looked over my shoulder many times. At the end of the flat section Chris Cawley caught me.
I guess this is a long way of saying that if you want to be a runner, there is no substitute for running. But if you like skiing, ski fitness translates to running fitness to a certain degree. Tom Diegel who "won" the run in 1:44 (course record!) is an avid skier. Chris Cawley who was in 3rd is an Alta 'troller.
Asterisk. I was able to keep it going for 10 miles, but that was all I could do. Several tough guys and girls took a SECOND lap. Me, I barely made it to my car, although, part of that I attribute to just coming back after taking a month off. And three days later, I'm really sore, still.
And to bring it back to the Transvulcania, I marvel at what guys like Kilian Jornet can do. He skied a full season. Then suddenly, he shows up at a fully stacked ultra marathon, breaks the course record, and finishes in 3rd place. Not to take anything away from the incredible, awesome, stellar, break-through performance of Dakota Jones, my guess is that at the Transvulcania Kilian was both prospering and suffering from being a skier.