I have seen many tanks in my time here on RC, but Mutagen's is still one of my all time favorites, the only SPS tank I know of that was designed for top down viewing.
http://reefkeeping.com/issues/2002-06/totm/index.php
theres his feature, unfortunately the tank had some type of top off mishap while he was away on business and the tank crashed, im not sure if he has a new tank now or not, he isnt on the boards much anymore.