China Digital Times reports that a bus in Shenzhen spontaneously combusted. Fortunately, no one was injured, which is much better than what happened in Chengdu.
The bus that caught fire was number 320--a route that I don't recall ever taking. However, bus routes (that I am aware of) that are 3xx run from Bao'an district to other parts of the city that are in the Special Economic Zone. Such buses usually get beat up pretty quickly because of the long routes. One's I've been on are 331, 305, 355, 301, 311, 319, and 361.
From the photos of the charred remains of the bus, it appears that it is one of the more recent models (though not the newest buses).
While I was fortunate enough to have never encountered such disasters on a bus in Shenzhen, I did have some close calls. On more than one occasion passengers were worried about the amount of smoke coming from the bus, even though the driver assured everyone that it was OK. I've also been on a few that broke down, forcing everyone to cram on another bus.