I plan on hanging this thing on the wall using metal "french cleats" - probably from Lee Valley. These things have a pretty small "lift over height" so you can hang things pretty close to the ceiling if you want - and they're only 1/4" thick so they don't require much room behind whatever you're hanging. Despite their size, when anchored to the piece AND the wall, they will support a surprising amount of weight - over 450 pounds. Because I live in earthquake country, these clips, in addition to providing a secure vertical support, also also limit horizontal movement as well. As insurance, I plan to add a simple wooden cleat to the wall under the piece's bottom rear "stretcher" for the piece to sit on..
Because I'm going with these "french cleats" I will need a horizontal element at the back of the piece to attach one of the two parts of the french cleat. That means I need to leave room at the back for the french cleat. THAT means that I need the hardware BEFORE I make the english sycamore "frame".
(Note To Self: When a project requires special hardware - hinges, latches, hanging cleats, bench vises, etc. - GET THE HARDWARE AS EARLY IN THE DESIGN PROCESS AS POSSIBLE)
Just in case the wall on which this piece will be hung isn't nice and flat, I plan on beveling the rear inside corner to make it easier to scribe and cut to fit the wall. If I don't need to do that - well insurance is always nice to have - even if you don't have to use it.