The gray part in this photo is a case bottom for the 1:3 scale keyboard, showing where the Teensie 4.1 will sit and showing the tiny size of the motor that I intend to use for haptic feedback of key presses.
The USB cable goes through that jog in the case to provide stress relief when someone inevitably tugs on the cable.

The screenshot below shows a sketch (in green) of where the LEDs need to be relative to the key caps and how much space is available for a daughterboard. Check out this photo of an original keyboard and look for the labels "online", "local" and "kbd locked". The original red lights are below those labels.