"I initially captured 180 degrees of view in a 6,000 x 40,055 pixel image, but soon learned that Photoshop was limited to opening files with less than 30,000 pixels in either dimension, so I had to perform surgery on the original TIFF file to reduce the image to just under this limit."
I thought about that method as well and after taking apart about 3 scanners it stopped being fun. Scanner assemblies are really hard to work with. Especially that some of them strobe colored RGB lights instead of a colored sensor, some use microlenses, and some won't start scanning if they detect that the light has failed (and you don't want the light for photography, so you disconnect the lights but then find that it refuses to scan). However if there's a hackable linear color CCD that is 4 inches long that I can wire into a RPi that might be super interesting.
Stephen Johnson was playing around with this in the 1990's.
http://www.betterlight.com/field_photography.html
"I initially captured 180 degrees of view in a 6,000 x 40,055 pixel image, but soon learned that Photoshop was limited to opening files with less than 30,000 pixels in either dimension, so I had to perform surgery on the original TIFF file to reduce the image to just under this limit."