Here's a couple of quotes from the Pprune thread:
"Given the possibility of a flight to the North towards Khazakstan, I note there are 86 functional airports in Kyrgyzstan and considerably more abandoned ones.
Kyrgyzstan borders Xinjiang in China. An alternative would be in Tajikistan which also borders Xinjiang.
Flights to either State can be made without crossing Chinese airspace, especially if the inwards vector is from around the Andaman Islands."
and:
"Outside of China, significant diasporic communities of Uyghurs exist in the Central Asian countries of Kazakhstan, Kyrgyzstan, and Uzbekistan. "
I want to go along with the speculation that the aircraft has landed somewhere in those areas, solely because I think that's the only way anyone on the aircraft could have survived.
But there's one big problem with that: If it's an abandoned, or little used, airport, it would have to be a visual, not an instrumental, landing, and I'm not sure that would be possible with such a large aircraft.