I find it rather hard to believe that something like this wasn't introduced during the Game Boy line's heyday. At least two models of an NTSC TV tuner add-on module inserted into the cartridge port was produced in the 2000s, and a similar product was produced in the early 1990s for the Sega Game Gear. Considering this, something like this could have easily been developed and mass produced back in the day, especially by the later half of the 1990s.