I reckon that my 600m f/9 apo-rodagon process lens should cover 20x24 with some movement. The thing just weighs so much, I think you can forget putting it on a wooden camera. I did take it past 1:1 with a ridiculous piece of aluminum extrusion as a rail, but you know what my problem was? Couldn't reach all the way from the darkslide to the lens to hand shutter it. :rolleyes: Now that is a problem, when you need an assistant just to pull a darkslide.
Besides all these glorious oldies, what about pinhole

Should be quite special at that size.