I knew a well known panoramic photographer that could not carry his 8x20 as many places as he would like. He carefully leveled his tripod and head and figured out a way to shoot two side by side 8x10 images and had THOSE stitched together to make the final image 8x20. The logistics are very manageable. He got to the point where he could get the images adjacent to each other to 1/16th of an inch. Competent assistants at the digital photo company did a great job of honing the results and the images were killer.
Another reason that he did it. He simply could not afford the ever increasing costs of color 8x20 sheet film and wanted to make color 8x20 images.
Necessity is the mother of invention as they say. If I could bear to say the word digital and not feel ill I would give this a go. It would be a heck of a lot cheaper and easier than "real" 8x20.
Just my $0.02.