I recently designed this portable mac mini (M4) case. It has a place to store a mouse and the mac mini (with acces to all the ports on the back) as well as a cable compartment. 
The top also features an Ipad stand. I don't know if everything works structurally but i put a lot of time in this model to make everything fit.
The compartment for the Mac does include a power button but i dont know if it will work. the cable layer has places to put in round magnets from 8x2 millimeters (4 of them) and the top has to be locked in place with small rubber bands. The most parts exist of two pieces that have to be glued together, so it can be printed on most 256x256 printers (the largest piece is 251 mm long). Everything has to be printed in PLA except for the mousemat, that one has to be TPU (the mousemat is optional). If you have any questions I'm very willing to answer them. If someone prints this I'm all up to get some feedback to improve the model. (this was my first time desining with Fusion so do not expect a perfect model)