I have on order 6 Cree XML. Won't be using them over an aquarium but right now they are the BEAST when it comes to insane light in small packages. Has the ability to sling out 1,000 lumens and it's about the same size (slightly larger) than a Cree XRE.
I also have a stash of other LEDs I'm going to put over a 45g cube.
Right now this tank will have LED overkill but I'm only going to drive these at 500mA or so.
The array will have three Meanwell drivers, two dimmable. The other, not (it's all I have):
2 Bridgelux 402 cool whites (roughly 5-8 watts each) and 8 Cree XPG neutral whites, dimmable.
13 Cree XRE Royal blues (dimmable).
2 Satistronic cold white (15K) 20 watt and three red Cree XPE (non-dimmable, driven around 600-700mA depending on how low I can take those huge 15K LEDs).
I have no idea what the final product will be, and honestly this is overcomplicating the LED stuff, but I'm having fun, earning geek points from my co-workers, and getting to play with a lot of LEDs.
Most of these LEDs are actually going to be "left overs" of some LED spectral analysis that I and a friend are doing. I'm putting together the drivers and LEDs, and shipping them to my friend in Wilmington for analysis of various LED combos, both for reef and fw planted tanks.