Hm, with previous versions it definitely wrote out all physical RAM, dunno if they've changed that for Vista. It's a pretty nontrivial thing to only write out used RAM, especially when hibernation is retrofitted to an existing OS (I think it was added in Win2000/NT5, thus retrofitted to NT4).
Anyway, back on topic: that development story sounds pretty horrible. Especially how long it took for commits to be pushed up the tree... I certainly hope the teams swapped code in other ways than that, having to wait 1-3 months before another involved team can comment on your changes? UGH!