Very nice that there is such a big scene of people modding this wallet and creating accessories for it. If I have the opportunity I will definitely try to create a high quality casing
I don't understand why would you need a high quality case for this? 
It's just a cheap DIY 3d printing that is available anywhere...
People did make premium metal cases for similar DIY devices like SeedSigner, but this is not needed at all and it can only attract attention.
What would maybe be possible would be fill the case with Silikone. Does someone has experience with that?
No.Silicone is used for isolation, not so much for cases and 3d printing.
From the paranoid tinfoil hat wearing department, be careful where you buy some of these boards from.
This is general used electronic hardware and it's not connected with Bitcoin in any way, and this DIY bitcoin wallets are not very popular, so I don't see any danger here.Official shop is always the best place to purchase stuff like this.