I actually think this image persistence problem might be partially responsible for all the banding issues on the LCD 46" Sharp Aquos LC-46D62U. Mine started out with no banding at all, but the last week it has cropped up in some spots, mostly noticeable where the black bars are at the top and bottom of the screen from letter boxing! I also noticed it was more noticeable on some connections, like regular RCA video jack, and less noticeable on SVHS in standard definition mode. On composite, playing a DVD it is hardly noticeable at all.
Going to hook my new HD-DVD player up in a while, and see if it is noticeable on there. Another odd thing is the banding bars seem to move around depending on what feed I am sending the TV. It may also be some sort of weird input problem, not related to the LCD panel at all.