+1^ Ecotech spicificly says don't mount them in an enclosed area and so far 12" off the water is as low as I've been able to go without everything closing up even at reduced intensity. As I said before someone is going to try it and it will work or not.
Are you sure? PacificSun are marketing their new Hyperion R2 LED unit, and it states that its only 2" above the water column. article and video here: Nice video demo of the PacificSun Hyperion R2 LED colors over a reef tank