This model is a vertical mount for the common 6 LED strobe flashers sold all over Amazon (this is the exact one I used). 

There are two versions of this design: One that holds a single strobe, and another that holds a strobe and a 4x12 LED matrix. The matrix just friction fits into slots on the mount. No glue needed.

The original intent of this design was to mount strobes on top of a virtual pinball backbox, but I'm sure there are plenty of other uses as well.

BOM (per mount)

• (1) 4x12 matrix (optional)
• (1) 6 LED strobe
• (2) M3 x 6mm socket head screws
• (2) 3x4.5x5mm heat sets (3x4x5 will work too)
• (2) #6 wood screws

Example