Here is a case for raspberry pi 3B+ I made in the form of a sega mega drive 2. I wanted to print one but could not find a free model, so I decided to do it myself.
The size should be alright i printed it myself 2-3 times , but the little stick holding the case close are very fragile, you need a good sanding and be carefull when openning/closing it. Normally you should only close it once if your project is to make a retropie / recallbox/ etc..
I don't plan to further this project anymore so feel free to costumize it as you want ;)
Please don't monetize is as I did this model because the existing one must be paid.
The modeling was made on tinkercard so i know it is not perfect.
Sorry for my bad english, I speak french.
Bought on amazon, I use PLA and did not try anything else
I did with 20% but i think you could do lower
whatever you want, but black looks good
you'll need support for the upper case, I did with cura and they were easy to remove. Don't print with a wall thickness uper than 0.8 and layer high higher than 0.2 as the sega logo will not come out good.