During E3, Nintendo admitted that the Wii U would not be able to run GameCube discs like the Wii could, but never said a peep regarding downloadable versions of GameCube games coming to Wii U. It looks like Wii U owners will get a chance to thoroughly employ that variety of storage options at their disposal.
Though McCollom's statement sounds pretty definitive, we remain skeptical, especially given Nintendo's track record with occasionally reneging on hardware/feature claims (how's that Wii DVD playback and USB storage coming along?). We've reached out to Nintendo for confirmation and details, and will update this post if we hear back.
Update: When asked directly to clarify whether the Wii U would offer downloadable GameCube content, Nintendo got back to us with this statement: "To clarify the capabilities of the Wii U system: As correctly stated, Wii U will not play Nintendo GameCube discs, however Nintendo has not made any announcements regarding downloadable content."