Node referrer widget, similar to flexifield or content_multigroup.

Issue Summary

It would be very sweet if node referrer would provide a widget on the node edit form (of the referred node). This widget would behave similar to a multiple-value flexifield widget, or the new content_multigroup, except that the created values would be independent nodes.

Use cases:
- One person can have multiple addresses. Address would be an independent node type, but they can be created / edited on the person node edit form.
- A person can be associated to a company, but this relation has fields: The person can be an employee, the boss, he joined in 2004, etc. person2company would be an independent node type, but nodes of type person2company can be created and edited on the person node edit form and the company node edit form.

Address and person2company don't need a body field, and they don't need a title (auto_nodetitle is your friend), so we only need to care about CCK fields. This will make the job a bit easier.

What we do need though is a weight field for nodereference, to allow drag-and-drop sorting of addresses or companies within a person node. Or we invent a new type of multiple value widget, that does not define an order.

Other ideas:
- For multiple value nodereference fields, the new widget would not create nodes, but field items. For instance, if the person to company relation is modeled as a multiple value nodereference field pointing from person to company, then company would get a node referrer widget to manage the associated nodereference field items.
- The same could be done as a counterpart to multiple-value flexifield with nodereference, or a content_multigroup with nodereference.
- This can be nested in arbitrary depth, but usability will suffer if it is too much. In these cases it will be better to manage nested stuff on a separate form.
- Big forms will be nicer if the fields of the associated nodes are in table columns.

Maybe this is all too much work, and should rather be done in a new module..
I searched a lot to find a module that does it, with no luck so far. They all do it slightly wrong.