This is a quick remix from one of the most used Raspberry PI 2/3 cases to fit the new Raspberry PI 4.

Edit 30-06-2019:

I made the first design based on the uGreen micro-HDMI to HDMI adapter. Amazon.de
The official raspberry micro HDMI cable has a bigger micro HDMI connector.
I added additional STL and step files to accomodate the bigger connector.
As I do not own the official micro HDMI cable I cannot confirm that it fits.

Edit 19-09-2019:
As user nophead pointed out in the comments there were two small slits in the bottom part (near the sd card). I fixed this in the source and re-uploaded all stl and step files.