I actually bought such a camera from Ebay a few weeks ago. Well, the camera is from India, beautifully made with 38" bellow, about 100 years old, I guess. It came with 2 holders which were not made to take today's sheet films. No problem, I have located a small shop in China specializing in wooden cameras and holders and they are custom making 5 holders for me as we speak. The film size as I measured is really 9 1/2 x 19 1/2", the ground glass is 10x20". I had searched high and low for films and by pure luck found 5 rolls of Kodak Aerographic Plus-X films 9 1/2 x 250 feet. I bought the guy's whole inventory which will last a few years for me.
I feel so excited about this project because this is my first ULF and the more I lookat this 10x20" size, the more I like it. One thing is certain, my picutres will look a little different than popular 8x20" and 12x20" ones.
Ask me any questions and good luck in your search.