Sometimes it’s just easier asking a woodworking friend to make something for you. Specifically, this cube shelf. I don’t think you could find this in a store anywhere. Not to spec, anyways.

MATERIALS: Simple mitered 6-sided box using 3/4” plywood, Wilsonart® SOLICOR™ Laminate in white. A steel keyhole hanger tightly draws the “shelf” into the wall.

DIMENSIONS: 7”x7”x7”