If you want to fill the space with mature plants you will need a light system capable of providing high umoles around the perimeter, where most lights fail miserably
I am about to put a BML SPYDR (3 x 3 footprint) in a 4 x 4 tent, but will only be growing one large plant
Solar Spec is shipping a system developed by a mj grower. His concept is 4 panels (size depends on tent foot print). Each panel is designed for piggyback power.
You can add lights as your budget allows, with a nice discount on the 4th panel. I think he has a system to cover 5 x 5.
He is sending me a 100 and a 260 to play with
I don't think website is up yet though