In my opinion the glare from the super high-intensity lights you'd need to keep the light that far away on a small tank would be enough to make me not want to do this.
Reminds me of the sunken garden vivarium with it's lighting hanging a few feet high:
Granted that had natural light to, but still. You want to keep the light up high for more viewing area?
Reminds me of the sunken garden vivarium with it's lighting hanging a few feet high:

Granted that had natural light to, but still. You want to keep the light up high for more viewing area?