I do have a good lamp in the "USE EXPOSURE". But they do a helmet lamp that is superb.
http://www.exposurelights.com/produc...joystick-mk.5/
Definitely not cheap but it is adaptable for helmet- Bike and hand held.
Never had the joystick but can vouch for the reliability of the USE lamps. Mine is 6 years old now and is one of the early versions that is just about as powerfull as the joystick. It has been dropped- submerged in a river- not been charged for a couple of months and it still works. AND is on the original rechargable battery.
But plenty of manufacturers out there- Yet another UK company with a good lamp is "HOPE"
http://www.hopetech.com/page.aspx?itemID=SPG66
This lamp is used by one of my riding mates and is helmet or Bike mounted. Not as adaptable to hand use but this one is powerfull for the size and is cheaper.
They also do a one LED lamp that is good and may be better for your use and is Cheap at around £70 at some online stores
http://www.hopetech.com/page.aspx?itemID=SPG64