Aside from the 10, 20, 30 watt multi chip LEDs, 100 watt and larger have been available for some time. They can also be had with different colours on the same chip. With optics, one or two of these would make a diy project much simpler with respect to number of components & soldering. Great option for deeper tanks I would say. Downside is heat management becomes a bit of an issue & all your eggs are in one/two baskets. You need a massive heat sink with fan & if that fails.... Prices have dropped significantly though, so replacement of a cooked 100 watt chip no longer hurts quite as much. The Kessils are similar, using a 30 watt multi chip I believe.
If I were to do another build, I'd seriously consider the larger mjulti chip LEDs.
Here's just one example of something I found with a quick search.
http://www.leds-global.com/100w-hybr...ium-p-306.html
And for the non-DIY folks, if you have deep pockets, here you go.
http://www.ecoxotic.com/100-watt-ell...annon-led.html