Dear Christopher,

We had the same problem for a digitization project of critical edition 
(the nature of the source is different, but the principle is the same). 
We have on file JPG per page and we have a XML TEI file for a book. We 
encode the logical structure in TEI file and we just use <pb/> element 
to indicate the beginning of a page. To resolve this problem, we use 
METS schema (http://www.loc.gov/standards/mets/). So we have two files :
- The METS files allows us to describe the physical structure of the book
- The TEI file allows us to describe the logical structure of the book

In METS file, there is the structural map section, for each page of the 
book, we have a section :

            <METS:div LABEL="page 64" TYPE="acte">
                <!-- A pointer to the file in JPG -->
                <METS:fptr FILEID="larochejpg_0100"/>
                <!-- A pointer to the file in TIFF
                <METS:fptr FILEID="larochetiff_0100"/>
                <!-- A pointer to the file in XML TEI -->
                <METS:fptr FILEID="larochetxt">
                     <!--With the precision in COORDS attribute the 
number what is indicated in the n attribute in <pb/> element in TEI XML 
file -->
                    <METS:area FILEID="larochetxt" COORDS="64"/>
                </METS:fptr>
            </METS:div>

In TEI file, we have this encoding :
<div type="acte">
                  <p>" Odo, Dei gratia Parisiensis episcopus, omnibus ad 
quos littere presentes
                     pervenerint salutem, in Domino. Noverint universi 
quod constitutus in nostra
                     presencia Guido de <hi 
rend="italiques">Levies,</hi> miles, laudante et
                     concedente <pb n="4"/>Guiburge[...]</p>
</div>

Next, we make the correspondance between METS file and TEI file with 
XSL. You can look the Website what uses this system. For instance, this 
page contains a deeds in text mode generated with TEI file : 
http://elec.enc.sorbonne.fr/cartulaires/laroche/acte50/ On the left of 
the page, you see a box and you can go to the page in image mode (so 
with physical structure) and this page 
http://elec.enc.sorbonne.fr/cartulaires/laroche/page53/ contains two 
deeds and you can go to the logical structure.

XML files are available for instance :
- METS file : 
http://elec.enc.sorbonne.fr/logix/ouvrages/cartulaires/laroche/larochemets.xml
- TEI file : 
http://elec.enc.sorbonne.fr/logix/ouvrages/cartulaires/laroche/larochetxt.xml

At this moment, we test this system for a transcription project with the 
digitization of the manuscript (it's a cartulary) and that works fine. I 
can't give you the URL, because the project is not totally finished.
I hope my explanations are understable, I can try to explain you better 
if you are interresting.

Best wishes
Gautier Poupeau