Well this is a shocker for me but it seems like Australia got around to implementing this much more quickly than I would've expected.
An article I just found on an expat forum states that China was added to the list exactly one week ago:
Australia has added China to the list of countries whose citizens are eligible for Work and Holiday Visas.
Implementation time frame: 21 September.
And there's only going to be 5,000 places per year for a country with an enormous population. So Chinese friends, apply now!
Update: My friend in China chased this up and tells me they only released the first 1,500 spots so far and those were all gone within minutes! No word so far on when the next batch of spots will become available.