Kodak makes sensitized glass plates in that size, but as they are made in
very small quantities, and mostly for scientific research purposes (glass
plates don't shrink like film, so the image size can be stabilized), they
are very expensive. You can find out more by going to the Kodak site
(www.kodak.com) or by calling their 800 number. I don't think you will find
the plates in any stores, either, but you can order them through any Kodak
professional dealer.
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/