Julian Ilett has constructed what his headline calls a 7,500 Lumen 100W LED Flashlight for under $10. It's a pretty monsterous construction, consisting of a stupidly cheap 100W LED, some wood and a chunk of metal as a head sink. Add to that two Ryobi 18V Batteries and the tagline price jumps a bit (say by $80-$90!). Even with that added it's an impressive monsterpiece of a camera killer!
I wouldn't trust it in anyway in its current form, but its seemed either did he! He's added a massive heatsink, a power control unit and swapped the Ryobis for a car battery to get something a little more consistent and shared it in this video