The first game I wrote I made my own level loader, and I had no idea that IRRlicht had an expandable factory class. Finding examples of it proved to be difficult. Factory classes are powerful in many ways, and can aid greatly to game development.
I've got hybrids state manager and a custom factory, something that all medium sized games should start from. Of course, if it's done right at the first time you'll find programming the rest of the game a breeze.
More realistically I'd be happy with it on the wiki somewhere. I could throw together an example and chuck it on the wiki, and get one the more experienced users to review it.