I'm also keen to retain some elements of a manual mill, i.e. be able to switch the spindle on at slow or high speed, and move the X/Y/Z axis manually in a variable spped jog mode (including rapid).
I've mocked up a layout of a replacement front panel in CAD, here's the first iteration. I've made this so it is the same dimensions as the existing operator panel.
The Ready and Fault are indicators only (not switches)