The librem 5 is somewhat modular. IIRC, you can disconnect and replace the modem and wifi card. So, I think a common chassis could have a screen, IMU, PMIC, bat

The librem 5 is somewhat modular. IIRC, you can disconnect and replace the modem and wifi card. So, I think a common chassis could have a screen, IMU, PMIC, battery, cameras, speakers, mics, leds, buttons, headphone jack, usb port and sensors (barometer, thermometers, light sensor, proximity...). The mainboard could connect to the chassis using some standardized common connectors for the devices provided by the chassis. Other devices could be connected to the mainboard: modem, wifi card, bluetooth and sd-card. That is not a giant leap from what librem 5 is.