Well, here is some new info regarding this camera.It was made by a company called Thornton &Pickard in England and was introduced in 1907. The lens is a Ross of London, Goerz 19inch Double Anastigmat f 7.7
The plate holders are designed for use with a 15X12" glass plate (if you do a search using 12X15 you come up empty, but using 15X12 you get several google hits). I will be having 2 film sheaths of the appropriate size made. The film is then loaded into the sheaths, and then layed in the holder as if it were a glass plate. The design is rather simple so it shouldn't be too costly to have made.

Strangly enough, now that I know the origon of this camera, I've run across several of them (in smaller sizes of course) on ebay. The 15X12" camera was referred to as a "full plate" and smaller size cameras were called "half plate" "quarter plate" etc.

I can't wait to make the first exposure!