Three things I never doubt about : the device won't be any cheaper , it won't be as thin and the battery life won't be as long as the industrial prototypes.

Now, what did I use ?

• For the hardware part :
  • a radxa zero,
  • a touchscreen (https://www.aliexpress.com/item/4001166217016.html?spm=a2g0o.order_detail.0.0.33e8f19cQXYw0B),
  • a flat external battery 26800mAh (but I used only the charger part and one li-po part),
  • a e-paper screen (https://www.welectron.com/Waveshare-18436-103inch-e-Paper_1) + the HDMI driver board (directly bought from waveshare)
  • some cables, ribbons, a micro usb expansion and 2 hdmi mini/micro adapters,
  • a 128Go micro-sd card
  • 3D printed parts

• Final dimensions : L 22.2 x l 18.2 x h 1.8