Right, if you want a set up that big, and that many plants, forget CFL really, you just won't be getting enough bang for your buck, and it sounds like you want to grow a fair bit of budd. I've never done big grows, I've just set up a 250w HPS, and that is more then enough to keep me smoking.
If you want to keep your box height down to 4 or 5 foot, may I suggest something more like 4'w x 3'd x 5'h, and put 2 x 250w hps, and have 2 rows of 4 plants. Alternatively stick a 400w hps in there and some CFL's for side lighting.
Ultimately, it all depends on what you want from your grow, and what space and growing considerations you have (noise, smell, neighbours, landlords, house mates etc). what grow experience do you have? I had a little look at your LED, and your plants look nice my friend, I'm surprised that LEDs can do it.
Oh yeah and even big cfl's can be a half inch away from the bulb, provided you have plenty of air circulation, just like trunks says. The problem is during certain growth periods you will be raising the bulbs daily.
Thanks for the rep...it's nice to spread knowledge rather then leech it off everyone else for a chnage