I live in China and I wish I could be of more help but frankly, the hunt continues to be frustrating. I may not have been too resourceful for many reasons (i.e. work, etc..) but the way I look at it, it'll be easier to source almost all choice parts from your local dealer. Things'll be in your language, meaning you know what you're buying, or the very least, the sales staff can explain/describe it to you properly.
If it helps, by far, the things I can easily get here are: 26mm carbs, 1/4 throttle, bling parts like gear lever, kick starters, brake/clutch levers. Yes, all cheap but thats mainly it.
High performance parts, as I've said are better obtained through your local dealers. I got a rear shock absorber - cheap alright but had to modify the valving for it to be good.
I live down South China and Beijing is far up North. I will be travelling there this week. I'll see what I can find out anyway.