They kinda kept a bit of that idea in the instructional video describing how the 'micro-gravity' of the ship would cause bone shrinkage. The 'x-ray' diagram showing the changes had the final human with small bones loosely arranged in fat bodies.
Saw it last night finally, loved it. The live-action humans were a bit jarring, but it doesn't really impact my overall love for the film. I dug the "mac" sound, too, even tho I'm a PC guy.
I loved that the villain's voice is... a computer program! Seeing that in the credits was hilarious. And how about those credits? The scrolling part reenacting the story in--I think--"8-bit" format was cute but didn't really 'wow' me, but the opening of the credits showing life progressing on Earth after the return of humanity, constantly changing artistic styles, was awesome. Great final image as the scroll began, too.
And Presto was genius. Can't wait to see it again, and Wall-E too! I may have to drop the cash for that fancy Wall-E robot