Okay, here's what I've discovered (and some of you may have beaten me to the punch, but whatever...)
Shiggy said: "We're developing Pikmin 2 and the Mario 128 that we showed to everyone at a press announcement earlier. You will feel something new in this game that wasn't in Mario Sunshine."
Also, I believe translated differently, was
"Pikmin 2 & the Mario 128 game that were shown at the unveiling of GameCube are now both in development. I believe that with this game [Mario 128] you will be able to feel the newness that was missing from Mario Sunshine."
Also, the day after they showed Mario 128 at Spaceworld, he said "I actually had more to show yesterday, but the PR division strictly said no."
Also, a funny thing is how the programming from Mario 128 was used for Pikmin.
Anyway, now I'm thinking that Mario 128 will be some kind of puzzle game... although that would seem kind of dull, considering what they showed for the demo... anyway...
"Thus has it ever been! Thus shall it ever be!"