Hi,
I've never seen one for WP (maybe someone else has).
Sometime ago I was shopping for something like this. There are some dedicated systems that do it, and document management can be amazingly complex when you start thinking about it, with versioning, checkout, user management, and so on. In my opinion this is well beyond a plugin. Unless the plugin is unbelievable. I finally gave up, and now I just use share Google docs with people. :)
But this one looks interesting.
http://www.opendocman.com/
Good luck.