I've been looking at CodeIgniter, CakePHP, and Symfony for a potential upcoming project.
It seems to me that CodeIgniter is the best fit for this requirement.
I've read a lot of conflicting reviews, many with the tenor of religious fervor. One of the least crazy is from Steve Jamesson. He leans towards CakePHP, but his application differs from mine.
If I were going to go with a framework (or change), I think Zend would be high on my list
These guys pretty much invented what we know today as PHP, and they have some of the best in the industry. I visited their office here in Silicon Valley, and it was kind of cool to see some of the people that have made so much possible to everyone.
I go by that area sometimes. I'll have to take a picture of their office sometime. :)