Opera Lamp

I have an '88 Caprice Classic Brougham LS. I'm looking for a part found on the LS trim level caprice brougham from 87 to 90 which is officially called an "opera lamp" by GM. Others may call it a "coach light" or roof marker light. It's a long slender rectangular flat light that is attached to the B pillar (the post that comes down from the roof between the front and rear door windows) on both sides of the car. It has been discontinued and therefore no longer available according to the chevy parts dealer. Would love to get ahold (buy) of one or two working units from possibly a used/salvage car that someone would be willing to part with. Anyone know where this can be had? I've come up empty so far.