I would like to source a manufacturer of IP camera hardware, suitable
for packaging into small discrete units. The lens / image acquisition
part of the system does not necessarily have to be integrated, but the
image processing, and serving to IP (over ethernet or wireless) needs
to be as simple and integrated a module as possible.

Are you looking for video over IP or something more sophisticated?  A
quick search for camera manufacturer ethernet turned up <a
href="http://www.dlink.com/products/?pid=295">http://www.dlink.com/products/?pid=295</A>