I had a thought recently that sounded pretty good, but I dont have room for it in my current projects. For an acrylic case, take some one-way mirrored tinting sheets and apply them on the inside of the case with the mirror side facing inward. If you have lights inside the case, they would be mirrored (and mirrored repeatedly at the right angles) while making the view into the case fairly clear. Something to set apart one of those $80 assemble yourself premade acrylic cases. Just a thought.