I created a stackable shelf for multiboard with an additional model for wall mounting using screws. The internal dimensions of each shelf are 220x200x55mm so while I designed it for these rugged boxes: Gridfinity Rugged Case "Light" 5x4x6U, 9U + 12U, other bins or drawers could fit within that profile.

For the strength, I was able to push down with decent weight on the shelf and I did not feel it even start to give or sound like it was under strain and currently I have 3 shelves with boxes full of nuts and bolts, with no issues.

Finally, for the multiboard version, I opted to keep a slimmer profile for the boxes I had in mind, thus the total height of the stackable portion of the shelf is 60mm, which given that multiboard is in increments of 25mm, means that while the supports and base shelf has pegs, the rest slot in and rest on that base shelf. To prevent sliding back and forth I put a single snap behind the shelf that protrudes enough to prevent the shelf from sliding removing something from the shelf, but even without it there is a lip that would prevent the shelf from sliding off of the one below it. I would use directional snaps to have a stronger hold on the shelf.