3D printers are just not suitable for this sort of project, believe me I have investigated this thoroughly last year
If you committed to 1 million units sure it would be damned cheap to produce, but even $10 each x 1 million = 10 million dollars up front. If there was some radical new hardware to put inside the machine (like FPGA based 060 speed A1200 motherboards etc) cool but you would be hard pressed to sell 10,000 cases of a single design to our retro community let alone 1 million.
There are other options but you won't like them lol
