Brompton front light recommendations?
The Brompton-listed set use a Busch &amp; Muller lights - the IQ Cyo with the SON and one of the halogen lights with the Shimano.  All of the B&amp;M lights use the same front mounting bracket to the top of the fork crown, so it looks like any of them would work.

Those brackets are also fairly easy to come by, and you could pretty easily modify any handlebar light to mount there as well - a piece of tubing and a bolt would be all it takes.  Or you can buy the official B&amp;M one.

As far as recommendations, it really depends on your price sensitivity and how much lighting you need.  I really like the IQ Cyo, but at over $100USD it's pricy. Of course, compared to the $200 EDelux, that's a bargain.