Up for sale is one Goerz APO Red Dot Artar 16.5in f9.5 lens in barrel. It is in nice condition: optics are clear with light dust, a few light scratches, no separation, haze, or fungus. The aperture moves easily and I don't see any oil. Non-original front and rear caps included.
According to http://www.cameraeccentric.com/html/info/goerz_3.html, it is at least 8x10. That document is rather old and I think this lens was made much more recently based on its condition and the materials used. In my use of it, I can confirm that it covered 8x10 with some movement, but I did not do any exhaustive experimenting. My results were very sharp with good contrast. Thanks for the interest.