Ok, sorry for the last non-rumor rumor, but here is an actual rumor, and one that will hopefully come true. If this happens, and happens soon, it could be the start of some interesting possibilities for the Wii.
The rumor comes from the Japanese gamer mag - GameLabo
Quote
The meat of the rumour, which has been doing the rounds on several US and European websites over the weekend, suggests that a Nintendo meeting took place recently to discuss the subject of an external hard drive for Wii.
While the story might sound a bit ridiculous on the face of it, fact is that many Wii gamers have already hit their limit on the Flash memory that comes with the console - especially if you've been downloading as many VC games as you can get your hands on.
Source - Computer&Videogames.comThis would be great for Animal Crossing, a Pokemon MMO, NeoGeo & Saturn VC games

, and whatever other uses 3rd parties could think up for a HDD. I know FFXI would probably be ported right away.
Remember all those rumors waaaay back when about the stand being a battery pack for the Wii? Well what if this rumored external HDD comes in the form of a slightly modified Wii stand, one that possibly has blue LEDs(like the disc slot) that glow when being accessed, and just has a little USB cord that plugs right into the back of the Wii. I think if they use some of those iPod mini HDDs and just insert it into the stand they could keep the Wii looking like it already does with its minimalist design and extremely small footprint.