I whined recently about getting a side-stitch at the Pineland Farms 25K. As also mentioned, I tend to stitch in races when I'm running at my limit. But I frequently get cramps in my left rectus abdominus/intercostals after running or skiing hard (always after stopping and usually while bending over to take off my shoes/boots). And I sometimes cramp in my toe abductors, for example after the Camden Hills run (remember that?).
This pattern of cramping fits in very well with some interesting recent research on the cause of cramping by a guy name Martin Schwellnus, who is part of a big sports science research group at the University of Cape Town. That group tends to be the thorn in the side of many traditional explanations of exercise phenomena such as muscle fatigue, which you can read about in Tim Noakes book the Lore of Running. And they've done a little work on the chi/pose method of running to avoid injury. Anyway, I think there is some decent evidence that hydration or electrolytes aren't going to prevent cramping, but there are other good reasons to maintain hydration and electrolyte levels, such as avoiding hyponatremia.