I had a similar problem a few years ago. While I never found the perfect machine here is how I have been introducing my now 10 year old son to the world of computers: - I bought him a Kano computer kit when he was about 7. The kit retailed for about $250 at the time and a kid could assemble it "like LEGO". It came with educational software that introduced him to programming languages, etc. (Unfortunately I do not thi…
When I was around your son's age, my parents introduced me to computers by getting me a LEGO Mindstorms Robotics Invention System 2.0 set for Christmas in 2001. My favorite thing in the world was the Exploration Mars expansion. The "hacker" community around Mindstorms was huge in the 00's. After the RCX was reverse engineered, all sorts of language support appeared. BrickOS for C and C++, lejos for Java, NQC, etc. I…
My college was still using the official Mindstorms sets for their intro to engineering classes, and so I recall finally getting my hands on the official Mindstorms software and finding it lacking. A classmate was using NQC to do it all, and his team let him do the programming. My team wasn't a fan of that approach so I stuck to the hardware.