From Sega Retro
The Video Jukebox, "nicknamed" VJ, is an unreleased accessory for the Sega Mega Drive designed by ASG Technologies. The VJ would allow the user to choose between up six Mega Drive games without the need to open boxes and insert cartridges on a regular basis, similar to how video game systems often operate in hotels or display kiosks. Cartridges would be inserted into the unit and would be selected via buttons on the unit, much like a regular jukebox.
Six VJs could be linked together to form a selection system of up to 36 cartridges, meaning in theory the average Mega Drive collection could be plugged into the console at all times. However, no Video Jukeboxes were ever released. It was due to retail at $49.99 USD, meaning a user would have to spend spend nearly $300 USD to cater for 36 cartridges.
Similar systems were planned for the SNES and Atari Jaguar, though these were scrapped too.