Ever dream of a title or sequel that never was?

I definitely do - I'd love to see a Metroid Prime take on the original NES Metroid. I'd also really like to see "expansion packs" for classic games - extra levels for Super Mario Bros., extra tracks for F-Zero, etc. I know that these things exist to some extent (ROM hacks, 64DD, etc.), but I'm talking more like official Nintendo releases, for all major markets, etc.

What would you like to see?