PHP5 OOP: Abstract classes, multiple inheritance and constructors

Example/working code here:

<https://gist.github.com/mhulse/5833826>

Couple questions:

1. Is there anything wrong with the way I'm using the abstract class?
If so, how could I improve the logic/setup?

2. Is there a way for me to pass $foo to the parent class, from the
child, without having to ferry that variable through the abstract
class? In other words, is there such a thing as:

parent::parent::__construct($foo);

... I want to have my abstract class constructor do things, yet I'd
like to avoid having to repeat myself for when it comes to passing
constructor arguments from the child.

Any tips would be appreciated. Sorry if silly questions.

Thanks!
Micky