Excellent example of stacked tray vertical. You need either a lot of training to flatten out the plants SCRoG style or a sea of green approach to make it work but a lot of people run these.
It's probably the easiest way to maximize vertical space but I've had many people tell me that above about three levels things stop being cost competitive. Reasons vary but it's usually about productivity.
I did vertical plane grows and those were much easier in terms of manpower but the training was critical to get the most out of them, plus longer veg times meant having to plan ahead further. I think stacked trays won because the SCRoG skills transferred easily and people stuck with what they knew.
I've done a couple of multiple plant per trellis grows and the results weren't better than a single plant; I was just able to shave a few weeks off veg times in return for a lot more brain damage later. I imagine a full on Sea of Green vertical plane grow might work too, possibly using the vertical strips from Bright Agritech, now "Plenty".