"A posting on Airliners.net saying that this was a code share flight with China Southern Airlines, and that only 7 pax were ticketed by them, including the 'Italian' and the 'Austrian'"
Well I do not believe in coincidences of this magnitude. We just need to see if they were travelling together, seat nrs, form of payment used for both tickets...this time they clearly did not choose to kill rail travellers at stations. They probably did not fully understand the difference between being ticketed on China Southern Airlines and actually flying on their aircraft. Still a plane full of Chinese pax heading to Beijing. Ideal target for Chinese Islamic separatists.
All seems to indicate a massive explosion that instantly disintegrated this aircraft, typically compatible with a terrorist attack (e.g. bomb), if this is not terrorism we are left with a missile attack or rare collision. Nothing else logically possible.