It should be simple. Three set of dice in a box, a lid that can be placed under the box or used as a dice tray.
You print in a color, you choose that that match the box color and here you go. You can even print the lid in a different color.
I place felt inside of the lid, that makes for a minimal dice tray. The green of the felt invites rolls.
The hex shape is more robust that the square shape and it is an immediate reminder of the gamely nature of the content.
The boxes are secured with rubber bands, the dice have a non-negligible weight (and they want to escape and roll).
I use Chessex dice in non-fancy colors, maybe to underline the impartiality required of the referee, more probably because they are easier to read.
One of the boxes contains regular dotted d6 dice, to keep the link with centuries of aleatory throws, Alea iacta est.
I print boxes with more depth too, should there be dragons.