This would basically be a combination of the N-1 switch with the Layers module:
The module has only one set of outputs. Only the outputs of the selected layer are sent to the modules outputs. As with a "Rack" module, it should be possible to add various outputs to this "Layers switch" module. And it would be good to have an "index" input that allows the switching of the layers through CV if need be.
One application of such a module could be the ability to switch between different synth engines by having only the selected one visible.