I custom build embedded computers sometimes.
They're fun to mess with.
I've made like, 3 of them with:
-A composite display I found at my local thrift store.
-A HDMI to AV adapter (those exist mostly for Roku(s))
-A battery (MUST BE 2 AMPS)
-Either a LattePanda or a Raspberry Pi 3B
-A cardboard box
-Some scissors
-Tape