I just added attached_node.module to the CVS repository.
There hasn't been much movement with document management lately from what I can tell. I've been working on it for quite a long time, and have changed my angle on it a few times by now. From the README:
Some code lifted from other modules, including image.module.
Purpose of this module:
Allow users to refer to other nodes from within the body or teaser of a node.
Provide a somewhat standard means of formatting the link to such nodes.
Allow user to customize position and attributes of this link/reference.
This is implemented for the most part as an output filter.
The most popular use case for document management in this crowd seems to be
attaching images to stories and blog entries. Arguments have gone round and
round about what is the best way to do this, and in the process of trying to
figure out what will make the most people happy, I have come to a compromise.
I originally designed a relational database model for managing attached nodes
and all of the maintenance code that goes with it. After much thought, and
coming across the filter that the image module uses, it occurred to me that
perhapse the best solution was the simplest one: use meta tags.
I took the concept that the image module used for tag format and made it a bit
more generalized. The format currently is of the form:
[node:NID, align="center", height="50", title="look at this stupid article"]