from your list, one thing I don't see is what was your food and drink intake in the 36 hours at 8500 ft before the hike (is it possible you were a bit dehydrated even before you started?). "Pre-hydrating" for 2-3 days, including electrolytes (cytomax or similar powder mix is an alternative to electrolyte tabs), is just as important as hydration during strenuous exercise.
Looks like I'll just miss you at Whitney - I'll be day-hiking it on Sept 1.
