I am pretty sure you could find a 2,000 lumen light with a way to mount it on your helmet today, but unless you are riding alone in dark mountains I surely don't think anyone should. If you are ever on a MUP, or even a road with a sidewalk next to you, you will really be obnoxious, if not blinding, to anyone going the opposite direction.

I don't see the need for 1000 lumens on my helmet. I also suspect that many of these cheap bright lights don't really output a real 1000 lumens.

I have a helmet light that is 250 lumens on high and 150 on low I think, but it is a high quality light with great optics. It has a great beam patter and is plenty bright to both see and get a drivers attention without totally blinding them.