There are several theories about what the banding comes from, and arguments against each.
1) The glass substrate itself is made with a faulty process. This seems the most logical to me, but then wouldn't the multiple other companies that buy glass from Sharp suffer from this too? And form what I know, they do not. Some have said it is the rollers in the plant that does it, but this does make any sense to me. That would mean the bands would be in the same place for all panels of the same size, and it sounds like it would be an easy fix.
2) Uneven back-lighting. The theory is that the back-light needs a certain distance to properly diffuse/disperse itself, and the thin Sharp design does not allow this to happen. But, other companies are getting thinner and thinner (certainly matching the 62 series thickness), and we are not seeing the same problem with them.
3) Problem stems from video processing/upscaling. I do find that I see the banding more with SD or HDTV programming, compared to true 1080p Blu-ray material. The problem also seems to change in magnitude when turning on or off certain video processing features. But it seems like getting a different algorithm into the processor to fix this, especially over the 2 year time frame they have had, would also be an easy fix. Then again, Sharp did sign a deal that trades their panels for Toshiba's computer chips....