I used to have an insanely complex but highly automated process to do something
like this between Freelance and an oddball app you'll have heard tell off:
Ventura Publisher.

If memory serves, it involved creating a VP file with links to dummy graphics,
one per howevermany slides we figured we wouldn't have more than.  Parse that
if you dare.

I'm betting it wouldn't be le science roquet to automate this in VP nowadays.
'Allo?  Bob?  ;-)

The trick is to make the links to carefully named/sequentially numbered files.

Slide001.PNG, Slide002.PNG and so on.

Then export the PNGs from PPT with these same names, pop them into place atop
the dummies, open the doc in VP, the links update with the new info and wallah.

Our ImageExport add-in would let you name the things and set the rez pretty
much as you like, unless you've had an attack of the sillies and committed to
doing this in 2007, where image exports are pretty well farkled, at least in
SP1.  

Then again, if the notes pages view in PPT gives you all you need but facing
pages/mirrored footers, a little VB could whip through the presentation and put
a text box to one side on odd pages, to the other on even, add page numbers and
whatnot.  Not REAL footers, but if you don't tell, I won't.

-----------------------------------------
Steve Rindsberg, PPT MVP
PPT FAQ:  www.pptfaq.com
PPTools:  www.pptools.com
================================================