I'm no expert on china either but they are doing the wise thing in trying to insulate themselves from the collapse of the dollar in bypassing it's reserve currency status. That being said china has huge banking and construction bubble problems of it's own ahead. our govt builds bridges to nowhere so a senator can buy votes. The Chinese build whole cities to nowhere so their economy (gdp) won't collapse.
China will certainly have it's own problems, which is why I said when the shit hits the fan, do you think China will look out for its own or "back up the US because we're too big to fail"?
You're right, in no scenario does china fall upon it's sword for our benefit. Rcg has no fricken clue the implications of his oft repeated mantra the USA is TBTF. He thinks we can just print the money and make the debt go away or we pull (borrow) the money from the interplanetary central bank of URANUS.
China would stab us in the back a thousand times before they'd do anything of consequence to help the US. In WWII they loved us, by 1950 they were killing our troops in Korea.