Head, helmet, visor: RoC Pit Commando
Torso, backpack: PoC Duke
Arms: RoC Duke
Upper legs: Retaliation Airborne
Lower legs: Retaliation GI Joe Trooper
Rifle: Star Wars

I can't take any credit for this custom. A few years ago at New Jersey Comic Con, Boss Fight Studios showed off some awesome custom GI Joe figures. One of those figures was a modern take on Flash, GI Joe's original LASER specialist. Their version was a great mix of vintage (colors) and modern (vest, armour) elements. I changed some parts from their version according to what I had in my fodder box, but it is pretty close to the original