I don't know that China would want to get involved...The Chinese are patient as hell as well as conservative...I see them as sitting back and seeing where the nukes fall and then deciding to pick up the pieces (or letting the two nations obliterate each other, thereby solving a major headache)....
Of course if the nukes look like they will affect China, they may decide to do something against either nation (remember, nukes do not care what your political or other ideologies are) as an act of self preservation.
The Chinese posture alot, but I am not sure that they want to cause any major ripples.
I don't disagree with you. I do note that China seems to have some desires on Kashmir. They have control of a portion of it. I doubt they want trouble with India any more than India wants trouble with them. As for Pakistan, I still find it hard to beleive that China would help them gain the bomb. Now that was a long term stroke of insanity.