Recessed outside corner shelf unit

[Twoodman66]

I've been asked to build a two units like the ones pictured. The plan is to use 3/4 ply with 1.5 face frame with a rabbit for the ply leaving 3/16 edge,with 1/2 ply backing.  First I can cut each shelf out of a 24x24  piece making each one whole(much more material used) or domino 12"rips mitered.
Second I'm concerned about sagging. We would prefer no support on the outside.
Looking for suggestions here

 

[Mario Turcot]

I like the concept  [cool]

To prevent sagging I would use the floating shelf technique in the middle and near the outside corner, with 1" dowels. Your shelves would need to be thicker tho  [eek]

Mario