I still have my doubts that this will be a complete and total overhaul of the ride mechanism. Yes, they have learned their lesson from the DL SM redux, but 7+ months? That's terribly optimistic, even for Disney. As a PP mentioned, "late-2009" is open-ended and they could push it back, but you know they're gunning for the holidays, so if it's not up by the second week of December 2009, they'll extend it through the following spring.
Even if they had already ordered a new track, side-by-side cars, etc. I don't believe the timeframe is generous enough to tear apart the old ride and install the new. I think the last rumor floating around was the closest to reality: Same ride/track layout but with new rails (possibly smoother); a sound system to play music during the journey; a new entrance/queue configuration and new departure/moving sidewalk dioramas; and new visuals on the interior of the dome. That sounds about right for 7+ months.
I guess we'll have to wait until somebody snaps shots of them taking old stuff out and/or bringing new stuff in.... from the Contemporary, maybe?