After some more research and reading around the web I've found out that this system is unreleased, and probably was be based on the Atari ST 16 bit line of computers. There is some speculation out there that the console might have been a joint project between Atari and SNK, as a possible cheaper version of the Neo-Geo that normal people could afford. Apparently SNK and Atari's officies were located right across the street from each other in Sunnyvale, CA, and the execs from the two compaines knew each other quite well. People point to the overly large cartridge slot and the fact that "Mirai" means future in Japanese as evidence of this connection.
However this is all speculation. Nearly nothing is offically known about this console. All we have to go on is this mockup. We could only think about how cool it would have been to have a Neo-Geo console back in the day that didn't cost a billion dollars.