I would like to see the computer unit and drives unit detachable from the display (Imagine a kind of Mac Mini and an external drive fixed on either side of the back of an Apple Display). Then if anything went drastically wrong to an out-of-warranty Imac then at least the whole unit wouldn't be a right off. It would also mean customers could upgrade one item without buying a whole new unit. Apple already use the modular theme with the Mac Mini and it's various stackable add-ons. I once saw a Dell mini computer that clipped to the back of a Dell monitor - but Apple could do it so much better. I just hope Jonno reads this.
If you 'd use an Apple Time Machine along with the iCloud, you'd have the backup of any system or hard drive the moment it goes bad on you. Furthermore, you wouldn't need to go through any time-consuming transferring of data to a new computer as any other computers you have would already be synched, and the new once would self-sync.
It seems to me you are looking for a solution to a problem that has been even more elegantly solved.