Gotta love MTBR. Some guy is going to ride across a giant Chinese sand box and he's going to get advice from a bunch of strangers on MTBR? Scary.
As a footnote, a buddy of mine did a 1500 mile tour across western China on a hybrid Trek with paired spoke Rolf wheels. I remember saying, "are you SURE you want to ride low spoke count wheels in China?"
Long story short, he broke a spoke, went over the bars and spent the next week in a hospital trying to recall why he was in China.
My ideal ultra touring rig is a steel single speed 29er fitted with as much King and Phil Wood as I can cram on it.