I want a zombie
The iphone is a nice computer in a small box with a small screen. But what if they split the two - what if you could plug your iphone into a different screen and keyboard? Then you could have a 7inch nettop or a 10 inch laptop, both powered by your iphone.
The connection wouldn't be wires as you have on a conventional computer. It would be a slot-in connection (proprietary, of course) that would envelop the phone - looking at it you've never know your phone was inside.
Once you've made that leap, then the alternate form factors wouldn't stop at keyboards and screens but include power supplies, separate batteries and so on. You could have tablets (5 inch or 10 inch) or even change the display - an eInk display tablet with iTunes for reading matter would flatten Amazon's Kindle.
Apple ipod already has a wide range of accessory partners, so there is a ready group of manufacturers. Apple gets to provide a market for clones, yet keeps control of the end user experience and charges the manufacturer for the privilege. By keeping them dumb (because they are nothing without the iphone brain), the new class of device aren't really clones but zombies.
What's not to like?