This page is graphics intensive. It may take a few minutes to load. You know, I have never figured out why Atari had so many unreleased products. It boggles the mind to think about all of the great ideas that never made it out the door. Some say that Atari was ahead of it's time with some of these devices.
Many people feel that management was incompetent.
Whatever the reason, many products never made it off the drawing board. The 5200 was probably the largest video game system ever designed. Part of that was due to the controller storage bin that was located in the back of the unit, but the motherboard was quite large as well. Atari attempted to design a smaller unit that would be cheaper to manufacture. The result was a prototype for the 5200jr., which later became the 5100 prototype.