The Powercube enclosure is simply a cosmetic affectation, Lars. Empty calories, but could be loved by Cube fans, everywhere -- of which MacDoc is one and as am I, even though I don't own one.
As for a headless iMac, i.e.: an INEXPENSIVE Cube design, this would go far in aiding Apple in corporate sales and would be perfect as a client in an xServe network. Like Apple started with the eMac being an education only offering, Apple should offer a US$500.00 Cube-like design for business, only (such a product being offered to the masses would kill Apple's gross margin). No PCI slots needed, a basic GPU (with the 32MB Quartz Extreme minimum spec), USB II, Firewire 400 (if the client wants to blaze along using a Firewire IP network), no CD burning need apply, just a decently clock-sped G4 with Gigabit Ethernet and DVI (or even VGA) connectors. This would allow a company to swap out monitors, and the small form factor (with a retractable carrying handle) would make it easy for the IT guys to carry and even stack either as a cluster around adjoined desks or stack in the backroom, somewhere.
And most of all, the ambient volume in a fanless computer office would be reduced, significantly and make the work environment a little more pleasurable.
So yeah; I think a headless iMac would be more flexible than a Luxo iMac's neck

And Apple could STILL sell the Luxo iMacs to the masses.
Think Different, Lars