Wanted bed lighting, but also a waterproof emergency bright flood light which you can safely stick say to a fender or hood and aim to work (say busted tire at night) and was lithium for greater capacity and no leaky alkalines, and
found this Rota-Light which is pretty cool.
Not the cheapest, but the magnet is incredibly strong. The only upgrade it requires is that the bottom surface is hard plastic which is low friction and could damage paint, so I cut to size a couple of those
thin self-adhesive anti-skid furniture pads to the bottom, and now you can try to slide it as much as you like there is no chance you can move it unless you pull it off the metal first.
Can be aimed, and brightness is 4-settings from very soft to "my retinas are on fire" bright. I leave it near the hitch on the top passenger side positioned vertical rotated to aim to the back of the bed and it DEFINITELY lights everything up with one push of a button on top.