12"x12" Module Backplane with 0.5" grid of #4 screw-holes. 576 total holes.
This is currently our largest module backplane at a full 1-foot square. Copper on both sides connected to all screw holes to provide a chassis ground for all mounted components.
Easily enough room for multiple breadboards, connectors, power supplies, and prototype boards. Build smaller projects on smaller boards and them bring them together on this large backplane.
When setting a project aside, place it in a standard PCB rack (be careful if you have many heavy components installed).
Isolate different sections of a large project by layering these panels. Example: custom switching power supply design mounted on one backplane (layer 1), another backplane mounted on top of that to shield the additional sections of your project from the power supply.
Module holes: 576x #4 screw holes (0.116") on 0.5" grid, 5x 1/4" (0.257") for panel mounting or feet.
Contents: backplane PCB only, no hardware or additional components.