5' plant, even if including planter height is going to be tough unless using tons of cfls everywhere or the tube lights on the sides. If I were going to use that space I'd do 1 plant in a Rubbermaid tote, 10+ gallons, under a 250w HPS or maybe even a 400 if you can deal with heat well enough. Either one is overkill probably but having only the one plant I'd want it to have all the potential in the world. Top it many times and hope for the best. A screen would probably be recommended by most but that's not for me, although may be your best bet. I don't know.