This question is a continuation of my previous question here zend models architecture (big thanks to Bill Karwin). I\'ve made some reading including this article
Have a look at my project at GitHub. It tried to follow the principles of DDD, SOLID and OOP. PHP and DDD. There is no ORM inside but a hand-made Data Access Layer. Domain entities exchange messages. Presentation Layer gets a special kind of objects. You will find a lot of factories. They are intended to simplify unit testing and maintenace. I hope some techniques can be of interest for you.