Node reference - one to many

I've spent a lot of time digging through information about referencing a parent node from a child, when the parent node ID does not exist yet.

It seems that in general this will never be supported 'cleanly' as we do not have a permanent nodeID to link to until the parent node is created. There are some modules that seem to achieve this in some ways, but they have not been suitable in my application (to work within an iframe, such that the children are entered here before the parent is submitted)

My first question is if the form_build_id (seems to be a hash prefixed with 'form-') can be considered unique so far as using it to identify related nodes?

Next, my scenario is a parent form with an iframe within the form to attach one or many 'details forms'. I like this set up, as it allows me to use the management node feature in pageroute, to easily present the user with options of adding more, editing existing, and deleting these 'details' forms.

I need to have these nodes related 'the drupal way' as I also need to set up a calendar view which shows the details, and is still able to link to and pull fields from the parent node.

The solution I came up with is to execute some functionality when the parent node is submitted that will grab all of the 'details' nodes based on my unique identifier, and slip in the parent node ID reference at that time.

I guess I am wondering if there is already a module which might provide this functionality? or a more elegant way to achieve this. I did try this through taxonomy, but I was not able to relate the nodes well so far as the calendar view was concerned.

Thanks-