Hi, I'm a zh: contributor from Hong Kong, where the people can enjoy the freedom of expression and press. Thank you guys so much for your care of this situation. There really aren't a lot mirrors of zh:, but there are tons of sites that copied our database to start their own wiki sites, though I believe the number of these sites has decreased since the block.
Currently the majority of our contributors from Mainland China are using proxy servers or the https provided by wikimedia (https://secure.wikimedia.org/wikipedia/zh/wiki/) to go around the Great Firewall. (Actually we have a page talking about the different ways to break through the block: http://zh.wikipedia.org/wiki/Wikipedia:%E5%A6%82%E4%BD%95%E8%AE%BF%E9%97%AE%....) But even if a user knows how to visit zh:, I doubt he would have enough motivation to write on a site prohibited by the government... (who knows whether the government is watching).
So IMO the real problem is how the users could go around the block and reach us (having been living under the wall for so long, they already know how). Instead, it is how we could bring the knowledge, and more importantly the culture and the spirits of wikimedia, to the people (which is our goal, no?), and sadly, I don't think we could do that when the government says no.
Cheers zh:User:Lorenzarius