i think china would be happy with a conventional war. it would give them a great opportunity to decrease the surplus population and an opportunity to whine about the US being bent on world domination. rather than being like many of the socialist regimes of the last century that killed their own by the millions and be persecuted for it, they could start a war and send undesirables as "cannon fodder" and not look like the bad guy.
also, i've heard a bunch of stories lately that china is attacking the crap out of japan in techno-warfare. internet viruses and bandwidth overload are shutting down websites and servers. this could be practice on an easy target before they strike a larger target (us)
90% of the security alerts I get from my Symantic Firewall on attempted portal entries on my home computer originate from somewhere in China ( Chinanet etc .)