Best idea I've had so far to really maximize the unit, and be able to do maintenance, was a rack system. 2 layers (it would be tight I know) with trays filled with small plants and LED strip lighting mounted to the racks. You could flood and drain it, or top feed DTW. If the unit was on a roller it could be 5 feet wide and moved from side to side to allow easy access from either side.
I grew flood and drain for 10 years, and in a 5x5 tray you can fit 98-100 clones in 6inch pots that produced 20g per plant on a LOW average(30 per with the right genetics is easy). In a 40 foot container you get a little under 40 feet inside, and then you need space for equipment(dehu, AC, fans, ranks, CO2, air filtration) and movement, so lets count on 30 feet of actual grow tray space. That's 60'x5' of grow space if there is a rack with 2 trays, which is roughly 1200 clones in that amount of space. 1200 clones multiplied by 20g each is an estimated 24000g on average.
Originally my plan was just to do this same style grow but without the rack, allowing more breathing room and head space. 600 clones is still a lot of clones to have ready to fill a room, and the yields would still be awesome. Then the idea for the rack system hit me, and if it was operated correctly I really think it would be about the highest yield possible in the shortest grow period. You could obviously set things up were you cycle new plants in gradually and harvest gradually, but I don't really feel that would allow the room to fully be maximized. If I wanted to make this system perpetual, I would get multiple containers and stagger them to get a cycle.