The latest spyshot appearing on MacRumors and Engadget looks like a fake, in my opinion. Whilst the recessed keyboard, Air-style, is consistent with this blog's predictions, there's one detail that doesn't ring true, and gives the game away: the mike and headphone jacks. On all Apple laptops, they have grey plastic inner lining, whereas in this "spyshot" they appear to have a shiny metal lip, flush to the exterior enclosure. That just doesn't look pretty against a matt aluminum surface, and it isn't Apple's style to get a detail like that wrong.
Other points of interest - the alleged Macbook in the photo does not appear to have the new trademark bulge/taper design sported by the Air, and expected to appear on the rest of the range. Also, whilst several forum posters have argued that the image depicts a "brick" enclosure, tooled from a single block of aluminum this photo clearly shows a join where the top surface component butts with the side panel. (MacPredictions thinks the single brick of aluminum theory is far-fetched anyway, so this isn't the reason we think the shot is fake).
Update: There's something very un-Apple-like about the entire row of jacks featured in this spy shot. With the depth of the side reduced, it simply looks ugly, and a retrograde step from the neat flap solution on the MacBook Air. It's surely more likely that Apple's patented collapsible port door will finally see the light of day (see image above, originally from AppleInsider).
Update x2: MacRumors is starting to have doubts about the veracity of these recent spy shots. Roll on Tuesday!