Busch & Muller makes a fork crown mount for their IXUS line battery powered lights. The IXUS lights follow the German traffic code which means a relatively powerful light (depends on the model of course) on a very specified area which also does not blind the people coming towards you (unlike all the usual powerful led lights on the market)

I got my GF a fork crown mount that should be able to mount any handlebar mounting light
https://www.rosebikes.com/article/ri...der/aid:684703

And honestly it's not all that difficult to make one like that yourself, just get some wire, a piece of PVC and bend/glue/gorilla tape that thing together. The fork crown mount most often seen in dynamo lights is the most sensible place to mount a light in my opinion as you can still put it on and adjust light power when riding.