If you are a PlayBook Chinese user, we would like to introduce Readopia to you! Readopia is a Chinese ebook reader. It displays Chinese in vertical columns from right to left (直讀中文). You can enjoy thousands of free ebooks from the internet, e.g. Haodoo (好讀網站, http://www.haodoo.net/) with many classic Chinese ebooks.
A free lite version with basic functionalities and a pro version are available.
Can it support sideloaded ebooks like epub or mobi format?
Readopia only supports a uPDB file format, which is specially for Chinese with table of contents and chapters. You can download many Chinese classic books in uPDB file format from Haodoo (好讀網站). If you like reading Chinese eBooks, I am sure you can find lots of interesting titles there.
On the other hand, if you have some Chinese books in epub or mobi format, you will need to convert them into uPDB first. Then you can read them in vertical columns in Readopia.
We would like to announce Readopia 1.5.0. In addition to PlayBook, it now also supports Z10! The same purchase will give you both PlayBook and Z10, too.