I used 2 100w sodiums in a 19"x30"x6'tall box, they worked well. i passed them on to a fiend who is using them right now. still turning out nice plants. they were salvaged from outside security lighting.
disassembled, and reconfigured for what i needed.
However, do not think that you cant turn out something dense from floros. Another friend jus came by earlier with his finished cheese, from a clone i gave him a few months ago. Hes using only floro tubes ( 18" 2 tube T5, cheapy unit from HD), and 26w ge cfl's. this is what he brought to the table..real nice, it was deff had more density to it than i would of thought.