I've finished translating all the translatable strings for the CMS module, as part of my task at the GHOP . It's available for download on the translation website. I hope to complete the sapphire module translation in a few days.
I'm also done with the Sapphire module as well as the openid-auth module as well. Feel free to give suggestions for any of those Chinese readers. I hope to continue translating upcoming modules.
Anyways, the main difference between Chinese China and Chinese Taiwan/HK/Singapore is that China uses "simplified characters" and the rest use "traditional characters." The other reason it's separate into different regions is because usage of words actually differs. Words may sound correct to a Mainland Chinese but may not make sense to a Taiwanese. So yeah, it's mostly cultural differences. So if you were to convert simplified Chinese translation of Chinese (China) into traditional characters, they'd probably look different than the Taiwan Chinese translation.