Originally Posted by MechanicalMan

As someone mentioned, there are multi-mode red P60 drop-ins. In fact, there is one at DX (sku 26345). I'm going to buy a single-mode red drop-in for an L2P host and mount it with a Paul Gino on the rear rack mount, but I haven't done it yet. That will put the light a little low, but I think the location will be fine. Without a rack mount, you could use something like a Cronometro NOB. I saw this picture of a rear light mounted with a Minoura Space Grip, and that looks like a good way to do it. Those lights should probably be used with some type of diffuser. I'm not sure what would be best, but for lack of a better idea, I think I'm going to try DX sku 1918.