As well as bitcoin which other people mentioned (and honestly I don't think this is that large right now), you can also just take bank cards out of the country attached to multiple local currency accounts in China and max them all daily. Otherwise, make business invoices from overseas to support the foreign exchange control bureau's approval of your transfer. Or just drive through Laos to Thailand with a car full of cash and enjoy your 90 day visa on arrival as a Chinese citizen. There's a lot of options.
The simplest way is the "youhuitong" or "preferential exchange" service the Chinese banks offer, which is a fancy name for "bribe us and we'll circumvent the transfer limits for you."
