Hi, Essgee,
Welcome to the ISC and thank you for posting to our forum; I hope others can join my weak effort here to help you!
Try this Japanese company:
http://www.ehime-iinet.or.jp/ehime_e/co ... health.htm
They make a diaper that has gotten great reviews, tho we can't get them here in the USA, the diaper is the Super Refre made by Toyo Eizai Co Ltd
Perhaps they have outlets / dealers in China. Those are major cities you mentioned, so possibly Toyo Eizai is doing business in those cities.
Do your search work on line, you may find Chinese diapers and can line up a source, be it a retail store you can visit or a delivery service that will deliver your package of diapers to your hotel. I've done that each time I've gone to Europe; order diapers (such as Tenna) for delivery to my hotel. It's been easy and reliable.
Perhaps some can comment on Chinese diapers if you find some, otherwise we can only recommend the European diapers such as Tenna, Abena, Molicare from personal experience. If those ranges are available in China, you will have dependable diapers. The Super Refre from Japan is said to be an excellent diaper-we have no personal experience with it.
Good luck with your search and let us know, please, how you make out and how your trip experience was...hopefully great! Enjoy your trip!
Joe K