You can play a lot on an NES, but you know what you can't play on it? Stairway to Heaven. You could end all that injustice with an NES guitar.
Get Lo-Fi (via This Is Why I'm Broke) makes and sells various configurations of the guitars — single coil pick-ups and rosewood or maple neck will set you back $155, while humbuckers and rosewood or maple will cost a bit more at $180. Shipping to USA addresses is $30; international is $65.
At the moment there's a waiting list for every model, suggesting there's more demand for NES electric guitars than we could ever have imagined.
Next up, how about some Game Boy castanets?