But yes, many are not unknown outside China (perhaps inside China as well), and yes one of the reasons is the unavailability of their work. In Cinema China 07, I saw a beautifully digitally transferred The Goddess (1934) http://www.dianying.com/en/title/sn-1934
but also the single print of Spring in a Small Town (1948) on the verge of being damaged
http://www.dianying.com/en/title/xcz1948

Certainly more efforts should be put into preserve classic Chinese films and make them available to wider audiences.

Except Centre Stage, I can’t think of any other Chinese films about the history of Chinese film industry. In terms of big names, I think you may want to start from Ang Lee. His films are very accessible to Western audiences while still have strong Chinese perspective/philosophy. His early work, like East Drink Man Woman, Pushing Hands are very enjoyable.
http://www.dianying.com/en/person/LiAn

If you like action/martial arts, you want to see Jackie Chan, John Woo, Tsui Hark, and lately Zhang Yimou.
http://www.dianying.com/en/person/ChengLong
http://www.dianying.com/en/person/WuYusen
http://www.dianying.com/en/person/XuKe
http://www.dianying.com/en/person/ZhangYimou

Or perhaps you can start from this top 10 list:
http://www.dianying.com/en/users/top10.php

A frustration was that I did not know where to start with Chinese film. (With Japan in contrast, there were large numbers of subtitled classic DVDs with directors’ names that I recognised.) I will see if I can seek out the two films you mention above. I was wondering if anyone would be kind enough to tell me who are the directors and (subtitled) films that I should seek out?

On a more polemical point, is it fair to say that Chinese directors cannot challenge the acclaim that their Japanese peers have enjoyed? Or is this just because of neglect born from the historical isolation of China until the 80s?