SolarForce M3 head might make a good start. Bigger lense, more room to shove copper in. Driver in the normal P60 spot sitting under a giant chunk of copper with the Leds sitting at the top of the host. Lenses resting over the Leds filling up the rest of the M3 assembly, so no mulehead needed.
No, I don't like the M3 since it is not a standard P60.
Also, my search for batteries is over.
Hypothetically I cant get a minute or two of run time before it runs out of batteries. Of course some basic calculations show it might reach 5000+ lumens.
8 amps from and IMR battery straight the body of the drop in. If I do it through the body and the spring it is a bit lower. Even lower if through the tailcap.
I can tell you that 20 amps is obtainable (hypothetically) using a zero res switch and no springs.
Actually, SF does have such switch: http://solarforceflashlight-sales.com/product_detail.php?t=LF&s=41&id=198&sname=tactical&xpage=1&sh=1
Btw scaru, so far the AW IMR18650 still seems to be the way to go. We have some promising cells from Samsung and Sanyo coming from the far east, but that might take a while.
LG and Panasonic are out of this contest, no cells with according specs available and Sony have been tested and those are inferior.
Oh, and of course I will modify spring and switch. Using flashlights without any springs gives me a bad feeling about squishing them..