You know, it also occurred to me that just about any navigation at night would benefit from a red light.
Last year I was out several times with my friend on his father's sailboat at night. He'd use a dim/dying penflashlight to check out the engine's gauges, this was a 30+ year old boat, the gauge lights were shot. I handed him my arc but it was too bright. We were out in the East River off the Throggs Neck Bridge in New York City. You needed your night vision out there, alot of water traffic, floatsome, jetsome, etc.
Other than just to flashlight collectors and hobbiests maybe you could, as Ralls has pointed out, market directly to boating enthusiasts, pilots, hunters, police, military, EMS.....who knows.
Anybody else out there can think of a real world use for a good red LED light?