I also have them built into my hood, I have the coralife lunar aqualight. They work nice if you wanna see your tank at nite, but some say they help with coral growth too.
Tunze multicontroller 7095 has one built in with a 29 day cycle. There is also a dimmer by ice cap that can do it for you. Both may be overkill and or too $$$ for what you are wanting to do. I did a DIY moonlight and wired in a dimmer that you would normally see in someone's dining room. I checked the farmers almanac for the moon cycle and dialed it into the dimmer. It was kind of crude and hairy, but it did work. We can run it by Fry to ensure it is safe. As a fireman, I didn't feel safe with it, so I went to the multicontroller.
I also have them mounted into my hood and they do a great job of replicated the moon cycle, from what i see, they are also cool to look at at night, .....
I have the "Current" Led Moonlights that have the option to add on more led fixtures, very plug and play!!!