If you're looking for a way to add a bit of gaming history to your keyboard, then you're in luck.
For obvious legal reasons, the keycaps from MMi keycaps aren't named after the classic Nintendo device. Instead, the page simply lists them as 'MMi Keycaps Video Game Console Artisan'. Nevertheless, the resemblance to the Nintendo machine is unmistakable. The keycaps have a fair amount of detail to them, with the disc tray, reset, power, and open buttons all replicated in the plastic, as well as controller ports, memory card slots, and side vents.
The keycaps are available in Indigo, Black, and Orange and are handmade with resin and acrylic paint. They should fit most Cherry MX switches as well as many clones. There are also other keycaps available on the site, including this one loosely modeled after the original Game Boy (for $40).
You can view the full selection here.