The latissimus dorsi, one of the main muscles used during pullups is HIGHLY active during running. And I have data to show that it shows electrical signs of fatigue to the same degree as the leg muscles do during running (during 5K-intensity treadmill running in competitive runners).
The upper body helps transfer energy down to the lower body, which transfers energy to the ground. The ground then transfers energy back up to through the body, helping the legs spring off the ground (physics - equal and opposite reaction). During running, the shoulder going into extension (moving backwards) helps to pull the body down to generate these ground reaction forces...
Just watch a sprinter sometime and see how they "throw" their arms down towards the ground to do this. A distance runner cannot do this to the same degree, since it shifts the balance between power and economy the wrong way for a distance race...
Since it is VERY clear that the lats are very active during running and show very clear signs of fatigue, it is likely they could benefit from some sort of training. Pull-ups would be an excellent way to train them. Considering most of the shoulder motion is occuring with the humerus either slightly in front or totally behind the torso, concentrating on the upper most part of the pull-up is important.
Now, nobody has done a study to determine if doing pull-ups leads to increased running performance, but by combining the information out there, I would think that it would to some degree. Just because somebody can run a fast time without pull-ups does not mean they are not helpful. The same holds true on the opposite spectrum - just because somebody can do a lot of pull-ups (ie, a gymnast) doesn't necessarily mean they are a fast distance runner.
Hope that helps...