Aren't you looking for a case to make Lip synching Robot?
I made it with balsa and the woodcut which it was easy to obtain.
The face used the thin thing of 1mm for the Balsa wood. As for the balsa, the thickness more than 1mm does not let light go through.

How to make the Lip synching Robot:
https://www.instructables.com/id/Lip-Synching-Robot...

Step 1: Measure the Size of the LED Matrix.

The LED matrix which I have is 38.28mm.
Please measure the size of the LED matrix you have .

Step 2: Cut Wood

I decide size to cut in consideration of LED matrix size and the thickness of the woodcut.
I made a cube of 41.0mm X 41.0mm x 41.0mm from the size of the LED matrix .

e.g.

Face ... Balsa wood ( H 41.0mm ｘ W 41.0mm x T 1mm )
H ... 38.28mm + 2.5mm (Wooden board Thickness) ... 41.0mm
W ... 38.28mm + 2.5mm (Wooden board Thickness) ... 41.0mm

Back cover ... Wooden board ( H 41.0mm ｘ W 41.0mm x T 2.5mm )

H ... 38.28mm + 2.5mm (Wooden board Thickness) ... 41.0mm
W ... 38.28mm + 2.5mm (Wooden board Thickness) ... 41.0mm

Surroundings... Wooden board ( H 38.5mm ｘ W 37.5mm x T 2.5mm )
H ... 41.0mm - 2.5mm (Wooden board Thickness) ... 38.5mm
W ... 41.0mm - 1mm (Balsa board Thickness) - 2.5mm (Wooden board Thickness) ... 37.5mm

Step 3: Temporary Assembly

Glue the after of the Temporary assembly.
The back cover does not adhere to let a cable go through.

Step 4: Glued

I use a wood glue ,

Step 5: Back Cover

Open the hole and through the USB cable for the power supply to the case back cover .A back cover can be opened and closed using metal and a small magnet.

Step 6: Finish

LED looks bright if balsa wood is polished.You polish too much the balsa, and please be careful.
Varnish was applied to take out the feel of a material of the tree.

Enjoy! :-)