Actual link to the page for the lazy.

Here

But they sold out in the short time they were there.

I kinda doubt it, but I'm no expert. You could use the Wii U GameCube adapter though, I imagine.

Even better, the Offical 4-Port Gamecube-to-USB converter for the Wii U, which you can use to play on the Dolphin Wii emulator for PC.

The Gamecube has a way better controller, and that means a lot coming from someone who loves the N64 as much as I do.