At this point Nintendo is pretty much obligated to make "mini" versions of all of their systems. They've checked off the NES and SNES boxes so far, and next up is the Nintendo 64. I wouldn't mind a Game Boy/Color mixture piece of hardware or a GBA at some point either, but for now all signs point to the N64 Mini coming out at some point.
Either way Nintendrew managed to skip a generation and just craft a GameCube Mini of his own. The gist is that he slammed an Up Squared PC board inside of a smaller GameCube design, and loaded up an emulator. The unit also takes USB input. As the rule of emulation goes; the more powerful the system the more powerful the rig you need to run it, so Nintendrew isn't hopeful that Nintendo can actually mass produce a cheap GameCube Mini.
Still, for a DIY project it more than manages to knock it out of the park -- we still need that official N64 system before we worry about the GameCube!