Banding on Apple 23" Cinema Display

Has anyone had problems with color banding on an apple 23" CD or other apple flat panels?  I a m shooting jewelry (Imacon 528C -H1- - 16 bit files) on a middle gray sweep.  I have a small spotlight hitting the background behind it creating a glow with the tones ranging from a light gray in the center to a charcoal gray at the edges.  I am getting banding in the transition areas.  I thought it was in the file and tried for hours to get rid of it.  Changed lights twice, changed the angle of the light, tried  diffusion material, changed lenses, software, restored calibration files, monitor profiles, and recalibrated the monitor.  Finally tried a printout on my epson 2200 and the bands weren't  there.  So then I plugged in my old LaCIe CRT and couldn't see the bands there either.  Then tried it on a mac G4 powerbook and Mac Powerbook and had banding on both. Then I tried it on a cheapo CRT and there was no banding.   I have had this display for about 9 months and have never noticed this problem before.  Can anyone help me to determine definitively that  the problem is with the monitor and not in the file so I can feel confident about handing the files off to the client?  Also, if it is the monitor, is it a defect or a shortcoming of the monitor,  and can anything be done to correct it.  Any thoughts would be greatly appreciated.

Thanks in Advance,

Larry Stein