Here’s some wild and crazy speculation on the possible new iMac, due mid-2013.
The glass and the display will be all that you see from the front. There will be no lower band of aluminum.
The display will be sharp enough to be touted as retina, in that fonts will look gorgeous, but it won’t be as high res as the MacBook because you’re sitting further away. The guts will be entirely solid state apart from the fans.
If you absolutely require an optical drive there’s an external one available.
If you require a bigger drive for storage there’s the all-new Mac Pro as an alternative.
What you end up with is essentially a Thunderbolt Display with a MacBook Pro inside it; very easy to manufacture because of the small number of parts and the exotic parts brought down in price through mass production.
There will be grizzles about the lack of upgradability but it’ll be an ideal machine for the other ninety percent.