I understand this post is year old, which is ironically the reason I am posting this response. First off, some of the people who answered this question are right. You're never really going to find a PHP Framework that come "MVC Ready" right out of the box...necessarily. Seeing as the framework is supposed to be a foundation where Dev's can build upon it, following MVC. However, in the last year since this has been posted, some of the PHP frameworks out there have sure come a long way.
I messed around with CakePHP for a bit, even to this day it is a horrible, messy setup of directories and structure, there is no clear distinction between logic, it has quite poorly commented code, and everything is kind of crammed together in one bundled mess. That is not a rant on CakePHP mind you, that is simple truth.
Zend, is excellent. They provide excellent documentation & code commenting, have a very friendly community, and provide a very nice framework for developers that are novice, and intermediate alike. They have come a long way since the OP posted this.
And to the people saying that there is no such framework to answer the OP's question, they are right as I said above. However, they are also wrong as well. Zend, Laravel and CodeIgniter are amazing frameworks, and while they don't "give" you MVC, they definitely pave a roadway for you as a developer to create a beautifully built, MVC applications, considering that you, as the developer follow good MVC practices.
To those in this thread saying CodeIgniter is horrible. You are quite wrong, at least by today's standards. At the time of this post I wasn't into frameworks so I hadn't looked at it then. Therefor at that time it might have been horrible. But I use it ALL of my web applications now. They do a great job of creating a solid framework with an understandable directory structure, as well as give you some amazing tools to start MVC'ing away. They do a great job at logic distinction, they have an awesome community for support, and they overall provide a great, free framework which, again if you follow good MVC practices, can turn into some amazing applications.
To the main point. I wanted to interject my opinion on this subject. You'll never find that perfect, MVC built, out-of-the-box framework. However, if you utilize good MVC practices, and choose a solid framework such as Zend, Laravel and/or CodeIgniter you'll be fine. Because the raw truth is, that the MVC is up to the developer how s/he implements good practice and not the framework. The framework offers the foundation, the rest is up to the developer.
Good Frameworks to use as references
- Zend Framework
- Symfony 2 (Added after reading comment, because it is also an excellent framework)
Just remember when using these, it is up to you as the developer to follow the good MVC practices. There are tons and tons of tutorials out there on good MVC practices. I stumbled upon a gentleman's website that has some amazing guidelines, and he aims towards proper MVC, and so far his blog posts have been pretty dang good, and he is a great place to start learning.