For my embedded computer I used the Nvidia Jetson TK1. This tiny 5"x5" computer supports full OpenGL 4.4, OpenCV, comes with Ubuntu Desktop pre-installed, and has an external power supply. I wrote a TK1 Setup Guide as I set up the computer, which includes the methods for auto-booting the software and setting the hardware clock.
For my TK1 case, I laser-cut Phillip Burgess's clean and simple SneezeGuard design on Thingaverse.
It is connected via HDMI to Epson PowerLite 1761W 3LCD projector (unpictured here, but seen in later steps).