I agree, this is a wonderful idea.  I have felt the man pages to be
deficient in a couple areas.  One is in providing that proper
overview/datastructures/diagrammatic view needed to understand what it is
you are learning to use.  That is, the man pages typically focus on
instantiation, configuration, and use, not of understanding the underlying
principles or purposes for existence.  Example: I just recently looked up
null_mount for the first time.  While interesting and providing more
information than some man pages on "why this would be useful to me," I was
thrown into elements of layering that, apparently, I must go to the 4.4 BSD
specs in order to understand.  I don't like the prospect of that.  I'd like
to be able to delve a bit deeper without that sort of hassle.

There are some semi-distinct perspectives such a manual could tailor to
even within the system (not including OS backgrounds, for instance):
* learning to install and run a minimal system
* learning pkgsrc
* becoming involved with development of NetBSD and the internals of the OS
* learning security
* learning administration of multiple computers, networking, and tweaking
etc... etc...
Even the man pages could be written for reference, tutorial, overview,
interrelationship of commands and files, design, etc...  I fear that we
can't cater to all; to do so would mean a multilayered documentation system
-- a sort of peeling away the next layer to see what lays beneath -- sort
of like requesting Advanced Menus.  The environment is already in that sort
of structure -- working environment (such as window managers), working
within that environment (shell scripting, getting used to commands),
working on your environment (pkgsrc), working on other people's
environments (admin, source).  Why not have man pages to reflect this
structure?

As with everyone else, I am willing to help.  I like to think about design
and possibly I could be of some use that way.  I'm one half-year into
learning NetBSD administration.  I've been told I'm a good proof-reader.
So FWIW...

Erich