I still have pending to design my own take on a case. If you want to check existing designs for 3D printing there are some here:

https://www.thingiverse.com/search?q=Eink

https://www.thingiverse.com/search?q=E-paper

On my design I will take care that there is enough room to place a 10000 mA power bank. Of course no needed if you plan to keep this plugged permanently with an USB charger.

Just take care to order the right Eink display that fits the design and it’s also supported on the gxEPD library for the firmware:

https://github.com/ZinggJM/GxEPD#supported-spi-e-paper-panels-from-good-display

 I would suggest something above 2.7 so there is some render space for your calendar entries.

Till end of January 2020:

If you live in Europe I can print it out for free in black if you pay the shipping cost just send me a private message with the link to download the model and the display model you want to use.