Emulation PC for 4 year old:
i recently built a PC gaming box for a 4 year old and used GameEx Gamelauncher mode for the front end. Quick video showing it in action.
I purchased a refurbished mini Dell OptiPlex 9020 for $250 US and two Amazon wired Xbox 360 controllers.
The box runs several emulators under Retroarch and the latest MAME. It handles latest MAME, N64 and PSX with upscaling with ease and runs at full frame rate with MP4 videos. Its also incredibly easy to use due to GameEx Game