While I agree that this particular image is probably a fake, (and way too front-heavy) I think the idea has something going for it.
Specifically, I think that this type of design is very plausible. It's tight, but there's just enough space in there for a short-neck CRT and the CD-ROM(/whatever) drive. Fitting the motherboard around those two is trivial -- have you seen the size of Apple's recent mobos?
It also fits with all the rumors -- not an LCD iMac, but close in concept. After all, I don't think most people are about LCDs per se as much as they are about the space savings and "coolness" that they provide. This provides the best of both worlds -- uncannily slim, but still affordable.
Alex