I began doing the markup of the bibliography using the approach I've previously used in journal article markup, using <biblStruct> tags and a highly formalized structure. However, after getting a little way into the process, I've re-thought it, and decided to go instead with a simple <bibl> for each entry. The immediate advantage is that I'm now able to leave the order of elements exactly as they are, and include all the punctuation between and inside them without worrying about generating it. At the same time, the component items are retrievable for any purposes we want. I'm still working out the exact details, but this is a sample entry:

<bibl type="book" subtype="bibliography" xml:id="mercier_2005">
  <author><name><surname>Mercier</surname>, <forename>Alain</forename></name></author>, 
  <title level="m">Le tombeau de la mélancolie : littérature et facétie sous Louis XIII : avec une bibliographie critique des éditions facétieuses parues de 1610 à 1643</title>, 
  <biblScope type="vols">2 vols.</biblScope>, 
  <pubPlace>Paris</pubPlace>, 
  <publisher>Champion</publisher>, 
  <date when="2005">2005</date>.
</bibl>

I'm still working out details of how to handle series volumes, because the <series> element doesn't allow <publisher>, <pubPlace> or <date> inside it, for some reason.