I had a project that required a background image to fill in the entire background of a website. The technical limitations were to have it totally done with CSS / JS. I did some research and found an example at giltman.com – so it was possible. I found some resources that used CSS alone but was yet to find one that scaled and fit all the image in the background with no background spaces.
I came across a great jquery plugin that did exactly what I wanted: Supersized jQuery Plugin.