I recently bought a white mac book for repairs on ebay. It had a water damage. Keyboard, cam and builtin LCD, didn't work.
But it works with an external monitor. I glued all the parts of the mac book on the back side of an 22''LCD screen.
Not like a real iMac, but it works and is self made.
Would have been also a nice idea, but as I'm already used to an iMac, I liked the idea of having a neat table with no wires or a computer box. the keyboard and mouse are also wireless. The mess behind the LCD screen I don't see from the front side.