I copied your reply into Wiki as well, see at between "Observe and Prosper" and "Real World examples" chapters.
::tup

On your other point.

the observer/notifier system is really written for a completely OOPs based application, as the observer expects to attach to a class that has notifiers within its methods. However a lot of the code within ZC is still procedural in nature and not contained withn a class.

To work around this, we added the 'stub' notifier class. So if you want ot create an observer for a notifier that lies within procedural code you should do something like
Code:
$zco_notifier->attach($this, array('NOTIFY_HEADER_END_CHECKOUT_CONFIRMATION'));
I seemed to have missed this from the docs