You would be surprised on what you can grow in a controlled environment. I am looking at a commercial strain that produces well so it offsets the total grow costs. So a fast well endowed fruiting is what I am looking for.
The most efficient lighting that I use is HPS, because of wattage used versus lumens produced. LED is just too expensive ATM, but it is the future. Running the lights vertically on light movers would be the way to go. From my reading I understand that Bananas are heavy feeders, so Hydro would be very beneficial to them since your supplying everything to them. In other plants that I've grown, the root mass stays relatively smaller due to supply being so close. Also in Hydro the total time frame to mature is cut by 20-25%. I am guessing a 55 gallon medium would suffice even when suckers are present and growing. I am still doing some more reading, but if you have something you can add....just post it.