My systainer shelves are ladder frames made of 3/4 in solid wood on 14 inch drawer slides to allow for full opening of the systainer while on the slide. The advantage of no holes for the feet is that I can slide a systainer back into its home without pulling the slide out.
The downside of this construction is that the shelves are thicker than needed and there is the empty space created by the feet. (Switch to metric) If 9 mm plywood with holes for the feet would be stable enough, I could gain over 20 mm for each shelf. With my current 8 Sys1 tall unit, I could gain another Sys1 easily and maybe a Sys2 (16 mm spacing on the vertical holes for the drawer slides). I am still considering how to mount the plywood to the drawer slides. I am thinking ofsteel L brackets.
If I ever win really big on the lottery, I will have a large batch of stamped metal shelves made and offer them here at below cost.
