Anyone know, or know where to look, how much RMB we can exchange for USD at the airport?

Don't know if the airport is different but the normal limit is buying $500 USD per day.

At the Bank of China on Dong Feng Xi Lu, you can buy more USD if you have ATM receipts on foreign banks, or FX bank receipts for buying RMB in China.

Plan ahead, or, Good Luck!

Limit is now $1,000. You can buy up to $1,000 USD per day at the airport or any bank that will sell USD.