Have you checked right here on Coroflot?
Creative Hunt is pretty good, but depends on what kind of designer you are. There was a lot more graphic jobs on it.
http://www.creativehunt.com/shanghai/jobs/
LinkedIn is ok imo, but a lot of companies actually hire through headhunters, so you might need a bit more experience to get a job through that.
I started working in Shanghai earlier this year. So far I’d say US is still a better workplace, but it really depends on your personal taste. Good luck in your search.