RFE: Nested bibliodivs

I am interested in being able to catalog DocBook bibliography databases
hierarchically, and for that I would require something on the order of
nested bibliodiv elements (as opposed to its current allowed depth of 1
under a bibliography).  I would like to tentatively ask that this be
included in some future version of DocBook.  I would also like to
generate some discussion here about the potential merits and/or problems
of this change, as well as potential alternate solutions.  With this
idea, bibliodivs start to look like DocBook sections (in terms of
nesting).

A simple way to change this, with respect to the DocBook "Bourbon"
release, would be to modify the bibliodiv specification to be:

    db.bibliodiv =
      element bibliodiv {
         bibliodiv.attlist,
         bibliodiv.info,
         blocks*,
         (db.bibliodiv+ | (db.biblioentry | db.bibliomixed)+)
      }

A slightly more advanced suggestion would have both bibliodivs and
biblio{entry,mixed}s in the same level.  This could potentially look
even more like sections, in that the biblio{entry,mixed}s would come
first and be followed by bibliodivs.  If this were the case, I believe
the model would look like:

    db.bibliography =
      element bibliography {
         bibliography.attlist,
         bibliography.info,
         blocks*,
         (db.bibliodiv+ |
          ((db.biblioentry | db.bibliomixed)+, db.bibliodiv*))
      }

    # later...

    db.bibliodiv =
      element bibliodiv {
         bibliodiv.attlist,
         bibliodiv.info,
         blocks*,
         (db.bibliodiv+ |
          ((db.biblioentry | db.bibliomixed)+, db.bibliodiv*))
      }

Interestingly, both have the same content model (both with these latter
changes and without, as far as I can tell).  Perhaps this could be
simplified further?

I would be happy to contribute any of the legwork surrounding this
change.  I look forward to your comments.

Take care,

    John L. Clark