Although (thinking outside the box..)
For what Mex is trying to do, perhaps instead of going the high wattage LED route and having to blaze a DIY path into uncharted territories..
Take a long look at high wattage CFLs...
For instance you can get a 65W CFL
HERE for about $11. This gives off about 4500 lumens.
Then use a reflector to concentrate and direct the light a bit..
Like
THIS for $7
Keeping in mind that the large wattage CFLs are about 12" in length and often will not fit into regular lamps but as long as you get the medium Edison base bulb it will fit any standard bulb socket. You do need to watch with these as they do come in larger base style and or may not have a built in ballast..
I have a 85W CFL in my garage which puts out more light than a four foot long twin tube shop light..
Need even more light, they make CFLs in even higher wattage levels like 105W and if I remember correctly 200W also.
Where I work at, they replaced ALL the high bay HID lights a few years back with six tube four foot fluorecsent fixtures.
We gained more light, less glare, better color rendition with a vast savings in power consumption and maintenance (paid a third party to rent a man lift and relamp the burned out HID bulbs every 3 months).
A year and a half ago, I changed out a 175W mercury vapor outdoor light at my parents house to a 42W CFL outdoor light. The 42W CFL is considerably brighter than the old 175 mercury vapor light ever was...