I have an idea about making the cases.
You would need to RP 4 pieces and use Silicon Rubber and possibly mold release.
But you would need a pressure pot to blow out any air bubbles... Otherwise you get wierd bubbles on the surface that will need lots of cleanup.
For those of you that have ever collected unlicensced garage resin kits... they are notorious for cleanup. Lots of sanding priming and painting. Then when you're done you have a nice photoshoot mueseum piece prototype but it's good for little else. Think of a nicely painted model kit when you were a kid. Sure it's plastic and painted but would you play with it? no you put it on display.
Belive me I've been through the ringer. To get a clean plastic case you have to tool it (steel mold) Or RP it with the most expensive method. An ABS injection color case is better in that it holds up to everyday use.