I created a new extension (a part of a set of extensions), which is
intended for improving categorization in complex languages such as
Chinese by supporting sorting pages in a category in more than way,
and is expected to be installed on Chinese Wikipedia.
This extension is a common part of all languages. Chinese-specific
part will be done in another extension, with the hook,
CategoryMultisortSortkeys, specified in this extension.
Please have a look at it.
Repo on Gitorious: http://gitorious.org/mediawiki-categorymultisort
Extension page on MediaWiki.org