OK. I just have ...
... to tell you my own thoughts about that image.
I think it's real.
This was apparently cut out from some (preprint?) promotional material, folded up and scanned in later.
Look at it. The perspective is just perfect for an add. Makes the machine looking big and bad. (Certainly bigger than it is - I hope it's just as bad-ass as it looks, though.

)
The raster is above the wrinkles because it was produced by the scanning process. The lower left corner was blurred after scanning, so it's above the raster.
There are no reset or eject buttons on current PowerMacs so it's likely there won't be any on the new ones.
The reason the lower handle seem 'further away' from the case than the upper one is, because there are probably some ports located down there - possibly along with a headphone jack. (Seem to be covered in the picture somehow.)
Looking at the media slot, the tower is a bit smaller than the current ones - which fits previous rumors.
The cover above the slot loading drive might be larger than that below because it would need a hinge to accomodate a drive with tray.
I agree with others that the minimalistic design fits with Apple's current lineup (PowerBook, XServe) - and it draws a hard line between the older PowerMacs and the new machines (which is something that Apple would clearly want, considering the less-than great reputation of the current G4's in terms of computing power).
So while I'm not _sure_ this is real, I can't see a single point that would rule it out.
That said, I don't like it. Looks boring to me.
But then again I also like the design of my old b&w G3 better than that of my new MDD PowerMac. So YMMV ...
bye. Andreas.