That would seem likely.

Official Nintendo 8 GB storage cards.

That would be an interesting solution but it is highly unlikely.  Nintendo's best interest is to enable those who already buy plenty of Nintendo products the opportunity to purchase more and the higher the cost or the harder they make it for them to do so the more money Nintendo loses.  

Nintendo has a tradition of selling accesories with games, started with Duck Hunt, passing through Star Fox 64 and recently Link's Crossbow Training. So it's highly likely they will sell a 4GB SD card with a game, but since the accesory isn't as appealing as the new wiimote that comes with wii play the game has to be a guaranteed system seller.

Animal Crossing would be a good game to bundle with an SD card, you could save items in it and transfer them to a friend through it if there someone doesn't have internet! But I'm not sure if Animal Crossing is a system seller, maybe just in Japan... Of course the cost of the game would be huge because AC must cost considerable money to develop since it has many elements.

A low cost game I believe will sell greatly (but isn't officialy announces yet as far as I know) is Nintendogs Wii. Seems like a very low cost game to develop giving all the profit it could bring from millions of copies sold, bundled with an SD card would make sales go through the roof. I consider it Nintendo's best option for bundling a SD card with a game. But maybe I'm just crazy...

Many elements does not really mean more cost. GTA IV cost all that money because of heavy work refining those elements.

I am not a specialist but I think that if a 290 (maybe 40 MB) blocks VC game does over one minute just to be copied then this could mean that the wii is not capable of reading games fast and mainly directly from an SD card.