I am in the market for a couple too and am going to see what I can find at the local AutoZone or the like sometime this week so I will let you know if I find anything interesting.
My merc tank has a modified outdoor fixture with a fluorescent bulb and red velum over the lens. This works very well for the hex shaped tank but won't do for my current needs. My nocturnals tank has a red LED Dome light (the LED's may actually be white with a red cover) and I may go that way again for the briareus tank but I thought I would look around some first. We have had a regular LED aquarium stick type night light that could be set to red only but anytime the power went out it reverted to white. After a summer of frequent power outages due to thunderstorms, we stopped using this one.