As an engineer who works with and designs with Hi-Power LEDs on a daily basis…
LED headlights are possible but require some pretty heavy engineering with thermal management, and optical design to get the pattern right and the output levels correct. And even with this the size of the lights have to be fairly large in comparison to most modern headlights.
We’re working on something that would be similar to output intensity wise to a single 35/50W HID bulb (What’s the standard Automotive headlight), and it’s about 8" x 4" in size, outputs about the same as the HID and falls off light output about the same, but costs a LOT more, not to mention the many many hours just in the optical design.
LED technology has come a long way and there are some VERY powerful LEDs out there, but without a lot of effort, know-how, and $$$$$$; headlight technology is not really ready yet.
The A8 and Bently are exceptions, and where $$ is no issue and Hella/Goodrich is backing it, it is possible.
Not even mentioning the power and heat-sinking required for the amount of heat generated by the LEDs is a LOT more than a HID system, even an over-driven 35W HID system.
If you want something unique, over-drive a 35W HID system; run a 35W bulb with a 50W ballast; This is not something that I’ve seen done very much, but it adds about another 50% brightness to the bulb.