"I use a 24" flat panel widescreen (16:10) monitor set to 1920 x
1200 in portrait (vertical) mode. I've tweaked or montaged a number
of free images into vertical 16:10 desktop wallpapers in Photoshop.
For example, the first image, Eagle Mountain Mist, is a montage of
six images, and lots of Photoshop "mist" (you can also see it on
Flickr). Some have been rotated to work well vertically."