I remember back in college in the early 1980s, I encountered light “pipes” twice – both times in cars. The first was my old Datsun B210, and a couple of the dashboard switches were illuminated by a light pipe. The light bulb for the indicator was deeper inside the dash somewhere, and it was routed to the switch in some kind of fiber pipe. This was like a 1976 car, so I don’t think it was using fiber optics as we know it today.
Another car was a Cadillac that a friend borrowed from a family member for a week or two. Along the roof line on the driver’s side, just above the windshield, was a row of what looked like LED indicators. But they were not LEDs, of course. They were light pipes which snaked through the car to each of the four corners and monitored the parking, hazard, brake, turn signals, and reverse lights. If you had a blown bulb, you’d know it before being pulled over by a policeman.
This doesn’t answer your question at all, but maybe it will inspire an out-of-the-box solution.