first off, in case you're living under a rock, the max and alt are built in the same plant, that alone implies platform and parts sharing.
we already know the 06 altima and max shared a bunch of parts but not so many exterior pieces.
now look here
since the photos are not the exact same direction, but i've seen many other photos.
my comparison here is how the cadillac BLS uses the saab 9-3 doors but has a bit of a black part on the C pillar to distinguish the BLS greenhouse from the Saab. I think we have this going on here. If you look at the fender to a pillar transition its about the same. the mirrors look about the same. Look at where the door handles are. The side door glass is likely shared parts I bet. The metal door frame around the window is the same I bet but the arc of the roof line is different. This is the BLS analogy. The rear part of the roof on the maxima is thicker and has the buttresses. On the Altima there is some black filler behind the window sill on the C pillar that is not on the maxima. I bet the lower door structure of the alt and max are the same.....the altima has a different door skin with the falling character line. But looks again, the arc/flares around the wheels are almost identical and look at the door cutlines are over the rear wheel. loosk the same. The front clips are slightly different and the hoods and front fenders are sculpted uniquely, but i bet the crash structure is the same. the rear of the alt has the most differences from the max, and is pretty much all unique, but again, the rear decklids while unique are similar enough to suggest innards being shared. Those headlight cluster outlines look too damn closes also.
Ghosn would never spend the money for these cars to be so different yet look so close.
Don't buy for a minute that the Altima's platform is "all new"....my guess is its revised a fair amount, but still has a fair amount of commonality with the current max. nissan wants to build these cars in the same plant, with flexible production based on demand. and if they can, share parts without people knowing.