I think a few missed the 0 in the topic title. 10 million copies is a lot, far more than any Zelda or Metroid has ever sold. Only one 3D Mario ever broke 10 million, that being Mario 64. Myself, I don't expect Zelda Wii to outdo Twilight Princess' sales by much, if at all, and Other M will likely have trouble breaking a million units. Galaxy 2 I expect will fare better than either, but not by a lot. It will likely cap somewhere between 5 and 6 million units, unless I've missed my guess.
As for likely future 10mil+ sellers, I can think of only one in the pipeline: Wii Relax. If they made a sequel to NSMB Wii, assuming the quality was up to par, it could easily break 10 million too. Obviously Wii Fit Plus is a shoe-in for that status too, but it's already out.
EDIT: Erm, am I the only one who's actually looking at past sales trends, current information on products, and logical most-likely scenarios to extrapolate sales figures? Because I'm really getting a serious "I wanna see it happen so it can happen" vibe from a lot of these suggestions... Just sayin'...
Sky Render - Sanity is for the weak.
