Hi Pablo and welcome to the forum!
There are tons of examples for 3D printed case designs, but all of them are for previous versions of the KCeptors.
Here you can find just a few of them:
There are no guidelines. The KCeptor has a very low consumption profile, so overheating is not a problem, you can go with a completely closed case. Just avoid metallic parts as screws, etc, since they might cause interferences with the magnetometer lectures.
Something to keep in mind is designing the case in a way that prevents PCB torsion, since it leads to wrong lectures on the sensor. That's why the current socket we deliver has that particular shape. Take a look at this post:
In general it is unlikely for a closed plastic case to transmit deformations to the PCB, since it normally contributes to make the whole more rigid. But it doesn´t hurt to keep that in mind while you do your design.
I see you are one of our backers, so I'm giving you the Kickstarter badge.
Let us know about your progress! and if you want to publish your design it would be a great contribution for the community!