Does anyone know what peaks in the area he's climbed before - so we can cross them off the list? Have the ground teams found any summit registers yet? Which ones? so we can cross them off the list. Speaking for myself, I wouldn't go out Muro Blanco under most any circumstances. Taboose is far and away the most desirable way out. If you can't make it through the howling wind, you sit tight then wait till you can. If you're hurt, you won't get far down the S. Fork anyway. So you'd sit tight and try to build fires. To those going up to help search, has anything changed? are you coordinating in any way w/SEKI?
Not finding a camp makes me think the worst, that he fell with full pack on while going x-cntry. I'd look carefully on both sides of the north ridge of Pinchot. As reconnoitering the JMT is a waste of time, perhaps he went to the lake just north of Pinchot pass then turned SW to cross at 3720m+, descending to the White Fork, with the idea of heading NNW over 3740m+ and looping back to Bench lake. Easier might be to cross Pinchot pass N to S, then head up to cross the N ridge of Crater Mtn, bag Crater, descend to White fork as above, loop to Bench and out. It's doable in 4 days.
Good luck to all searchers.