Probably unfeasable in practice, but not enexpected given that:
"China holds US Treasury bonds worth $739.6 billion as of January. It is also the world's largest holder of US dollars as a reserve currency, holding more than $1 trillion, according to US government figures."
http://www.dw-world.de/dw/article/0,,4126017,00.html
"Standard Chartered Bank (STAN.L) estimates that China, the world's largest holder of U.S. debt, held $1.45 trillion in U.S. securities at the end of 2008, out of a total $1.9 trillion in foreign reserves. As America starts spending $787 billion to boost the U.S. economy and another $1 trillion on its cash-strapped banks, Beijing is worried inflation in the U.S. could erode the value of its dollar holdings."
http://www.businessweek.com/globalbiz/content/mar2009/gb20090325_407723.htm?chan=top+news_top+news+index+-+temp_global+business
Obama's stance is that "the dollar is extraordinarily strong right now."
And note that ""Zhou is well aware that the dollar's position is secure for now." Indeed, the same day Zhou called for the new reserve currency, China's State Administration of Foreign Exchange issued a statement that it supported the dollar and would continue buying U.S. Treasuries."
Another sign maybe that the era of US hegemony is drawing to a close? Fortunately perhaps China has a (not unblemished) history of international non-aggression, unlike America when her interests are under threat.