Joseph,

 > I'll revise what I have, in that case. I'm getting the hang of this,
 > honestly!

nice (that getting the hand of it I mean :-); if people like you seriously
start playing with it we should be able to sort out the rough edges and
provide additional stuff fairly fast.

 > > it is a bit like the newcount newcounter discussion yeaterday
 > > ... \def:NNn is kind of an attempt to carry more or less "user-level"
 > > functions into the language and they don't belong there
 > 
 > On the counter discussion, you'll see (in xnotes2bib) I've stuck with
 > the low-level variant but needing to make it available to the user.  I
 > hope this is the right idea.

what we really need to do is to provide a user level interface for that, that
then can be reused at package level for offering user accessible counters

 > As I've said, I'm asking to understand things.

which is great 

frank