Barry H,
I just viewed the visiled page. can't tell much details. they don't go into spec's at all.
claiming a four hour runtime, with two luxeons. not that hard to achieve using 2x 18650 2400 mah li-ion cells.
amodotech sells 2x 18650, 2,400 mah protected li-ion packs for aprox. $20 ea.
one can drive 1x 3watt Kbin prefered with 1x 18650 in direct drive or with simple resister to limit current. there are a number of different boards available depending upon what is more important.
a 5watt's vf or forward voltagle is higher than 3watt. would need a board to boost voltage to required.
A very simple possible mod is to take a surefire U2's head and mount on a headband to a 18650 batt pack. but draw back is costs starts to mount up at $270 for U2. true not even close to $3K
advantages is you will have imediately a very reliable veriable 100 lumen white light source. please note lumens or flux is very hard to measure. lot's of bogus claims floating about.
general rule of thumb is a 3watt putting out 48 actual lumens out the front end is a very bright 3watt.
luxeon lottery count extra, a 5watt can range from 65 lumens to 150+ lumens out the front end. high bin 5watts are rare no matter how much $$$ you want to throw at a light.
then again you may be better off looking at HDS's upcoming 100 lumen headlamp system.
black diamond headlamp below is an excellent candidate for a luxeon mod using 3x AA cells for a Kbin Direct drive light.