Residence Permit vs. Work Visa

I am married to Chinese women. I have an F visa that expires August 11, 2011. Under the new rules I do qualify to apply for residence permit, which is what my wife and I want to do so that I can remain in China. however, it will prevent me from doing any work in China. This means I would have to apply for a Z visa. At what point in my entire residence, i.e., 5, 10 , 15 years etc, can I qualify to work as a resident of China without having to renew my work visa?