Well, I am from Taiwan, so maybe I can contribute to this topic a bit.
Taiwan's National Symphony Orchestra already dedicated the whole 2004-2005 season doing Mahler. How it was, I don't know, because I was still living in the US.
The Singapore forces already premiered the M2 and M8 during the last 3 years or so, as you may know. And now they are doing M3........wow, I guess they have huge interests in Mahler's big choral stuffs!
But I wouldn't expect too much about Chinese orchestras. Chinese musicians (no matter from PRC, Taiwan, HK, or Singapre) are way too conservative in order to "dig in" into the music as wild and emotional as Mahler's. Surely they can play note for note if prepared well, but it's too difficult for them to deliver a performance that can bring the house down. I remember when China Philharmonic did M1 in Taipei, the critics bashed by saying: "All the notes are there but too dreadful. All I hear is Brahms. Where the hell is MAHHLERRR???"
OF course, my assumption may be wrong.......