Trout, as above, there are lots of lights that are OK for off road.
The one gap in the market is a light system that is road legal, but f=ing bright, with a brief high lumens mode that also give offroad prowess!
The challenges are different, side spill, need for reflector on rear, ease of removing from bike. USB charging would be good (would enable a VERY small battery).
Go on, you know you want to!
Also my mate in steeton, wants a high power light to mount onto the front of his blue HASE recumbent trike!