I managed to get some engineering samples of the Cree MKR LED announced on /. a couple weeks or so back.
Needless to say, I was thoroughly impressed. I ran 12V @ 200mA, 500mA, and 1250mA. You know how us geeks/nerds say do not look into laser with remaining eye? You don't HAVE any eyes left with the new MK-R, even at a measly 200mA of direct current at 12V. At 1250 mA, I only needed half a second before the diode packaging began to melt the green PCB, the heatsink was absolutely ineffective. Be prepared to use metal SMD-mount boards for these diodes, because that cheap green board used for most SMD LEDs simply will not cut it. Pushing 15w in a 7mm x 7mm package, you need serious heat dissipation capabilities. Also, DO NOT HOLD THE DIODE WHEN DRIVING AT 200mA! You will blister yourself.
I no longer have my light meter, as I would use that to check flux levels and lumen levels, but needless to say, you drop a quad of very-efficient nearly 4-watt diodes into a single tight array like this, and the world is going to light up before your eyes. I would love to see one of these in a Mag-Lite. At 200mA, 500mA, and 1250mA, you would have all the light you need. Remember that commercial where the kids with the flashlight are using new Energizer batteries and it looks like they're suddenly using a 1,000,000 candlepower light? It's even better than that.
Just one of these would light up my entire 15' x 24' living room, quite possibly more, with wonderful light levels. I could see this sitting in the center of my ceiling. Two bedrooms, two bathrooms, living room, kitchen, dining room. Seven rooms, 105w operating power with all in operation. I could leave my whole home lit up for the same cost of a single 100w incandescent light bulb, which barely lights one room. Oh wait, I forgot the porch and patio. Make that 135w operating power. And in reality, even at 500mA drive current, I think that's more than enough light for an area roughly 25' x 25'. Still beating the pants off of equivalent incandescent or fluorescent. It's the end of them, and I already have the belief that these will truly smash HID systems.
I want single-color versions of these. Cree, if you're reading/listening, you have technology in your hands right now to take over an entire segment of the optoelectronic market. You dropped out of said market (and a couple of others) when you quit making 660nm diodes, and you could really take this class of diode to great heights if you could specialize single-wavelength versions of this.