A few years back I installed lights under my bumper (similar to your idea of IN the bumper) to help with scene lighting when loading/unloading my boat at night. Worked good for that, but when I'd go camping and try and use them, they seemed to make way too much glare. I ended up hiding LED floods up under the body of my truck where you can't see them, and that works really well for scene lighting, it's kind of like under-body light kit effect but much brighter (like rock crawling lights I think they're called) the good thing is that you don't get glare. The bad thing is you only light up a few feet around the truck, at least 6 maybe 8 feet of useful light.
I have contemplated installing LED pods on my roof rack, but maybe I'm over-complicating things.
Green circle=glare-prone rear facing lights
Red arrows=hidden LED floods
Blue circles=considering above-head lighting for more area without glare
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My 2cents is that LEDs within eyeshot will be very bright and may make for uncomfortable usage at certain angles. I'm not so sure a high-powered LED light bar at head level isn't gonna burn your peepers out if you accidentally look at it.