I'm not, by any means, dismissing the idea out of hand, I'm just not impressed by the sales spiel. In fact, the idea of covering hectares of land in little plastic boxes seems somewhat crazy to me: this criticism obviously doesn't apply to growing food where there isn't any available land. I'm just asking questions to learn why choices were made and to see if there's anything useful I can offer.

As I said, I've found that smaller containers require far too much work to make them successful, especially when they're relatively exposed to the elements. I'd say that even on the south facing Irish patio that we had in the last house the container size you have is barely large enough. Larger containers, with multiple crops in them, seem more stable under temperature changes and hold water better. They also form a more viable soil eco-system. I'd be inclined to experiment with 2x4 or 4x4 wooden containers 8" deep with buried reservoirs if I was doing what you're doing.

The issue of appearance may or may not be important: it depends on whether you want the space to be useful as a garden as well as a food production system. My inclination is to make the space somewhere you want to spend time - the best fertiliser is the gardener's shadow and all that.