Thank you for the suggestions.
The tank has a small fishroom behind it and a basement below for filtration. The lights will just hang behind wood panels in my livingroom so will not be seen.
I have done the canopy with retrofit lighting in the past but really prefer the nice clean look and ease of hanging fixtures rather than trying to raise and lower a canopy.
I don't want to go to LED other than to supplement T5's just to get the shimmer lacking with T5 only.
Maybe I have never found the right bulbs with MH's but I have tried the popular 400W bulbs and really don't see what all the fuss is about, my T5 setup always had better growth, colour and overall beauty.
Problem is I will need a lot of T5's over this tank and the cost of replacing them annually is quite abit more than the 250W mh bulbs, also the cost of the fixtures to fit this length and the fact that I would need more than one fixture front to back makes things messy unless I went with the Giessman 12 bulb fixtures??
I like the idea of just lighting the islands but have never seen this before, I always thought the light should be evenly spread throughout the tank. Anyone know of other tanks lit this way, any pics here on RC?