Moose or Meta?

Answer 1

If you truely want to do the Builder Pattern or the Abstract Factory Pattern then you can do that, and there is nothing stopping you. But perhaps what you really need is some Inversion of Control / Dependency Injection? For that, you can checkout Bread Board

Answer 2

Have a peek at http://code2.0beta.co.uk/moose/svn/MooseX-AbstractFactory/ and feel free to steal. (Mine.)