If you don’t want to use a bank card or a private money transfer service, you have pretty much eliminated all of your options.
The easiest way to send money to China on a regular basis would be to open an account back home and obtain an ATM card that is on the Cirrus network. Then your wife could use that card to withdrew money at any Construction Bank of China ATM terminal.
The only other way that doesn’t involve the direct use of a bank card would be to have your wife open a Chinese PayPal account that is associated with a credit card. You could then regularly send a payment to the PayPal account and your wife, in turn, could then have PayPal transfer the money into a local account.
I’ll ask Ken if he has any other ideas.