Hi, in fact that, i know that there are some CMS base on Yii, such as FlexicaCMS, but please forgive me that i think I need a CMS more powerful, such Drupal, Joomla, and so on. 
Today when i surfing, i found a CMS named TomatoCMS which base on Zend framework, it is powerful to develop, many modules,
But that, i like Yii so much, , i just hope that some one, some team will develop such CMS then Yii can play her good power. 
Phundament is trying …
But, not yet.
CMS is absolutely essential.Unfortunately no yii CMS yet .In my humble opinion,should be number 1 priority for yii core developers.
Yii should come with an integrated cms solution.
Let me disagree. Yii is a good tool to create very specific content management systems. Yes, I don’t like “universal” systems (because they don’t exist 
), but there are many Yii tutorials/extensions to build your own task-oriented CMS quickly. The main priority of a framework should be a framework (and a good documentation with many examples of course ).
I agree with andy…
Yii should evolve as what it is: a framework, a library were programmers use its potential to develop whatever they wish to do and Yii to be preference number one. In fact, Yii did an extra work by including extra libraries like Zii or Jui within it and I consider that as a gift. Nevertheless, its main objective should be to develop better algorithms, adapt to new PHP frontiers and technologies, and increase its responsiveness speed not creating a CMS… for that, there are their users.
It is already amazing… and extensions are making life easier and easier everyday…