Thinking outside the box- I assume you only use these offroad, and that's not an everyday thing? If so, why doesn't a light manufacturer make the bracket/light base so it really EASY to remove, then you can leave them off until you actually need them. Keeps them out of weather and the UV as well as not being stolen.
It'd take some fancy figuring and some metal melting/whittlin to do it yourself, but with a taper, or dovetail, something could be made to lock them tight with a repeatable aim as it's remounted. Maybe look towards the firearms industry's quick disconnect scope mounts for some inspiration.