Yes, it can be done. Four of us left at 06:00 and ultimately crossed what passed for a finish line at about 11:45. Conditions for the first half were okay, but the second half was a study in suffering. Hats off to my fellow travelers for their humor and seemingly boundless resolve.
Speaking for myself, I see no reason to repeat this experiment. I know now that it can be done, and that's all I needed to know. Complete ride report to follow.
Photos can be found here.
Photos can be found here.