I think the key point brought up here is that there is greater convenience in external accessories once there is more than one computing device to use them with

I think the key point brought up here is that there is greater convenience in external accessories once there is more than one computing device to use them with - and I'd say that's a much more common scenario than it used to be. My suggestion to Apple (or 3PP), would be to make a stackable accessory form factor (along the lines of http://www.123macmini.com/accessories/guide/enclosures.html http://www.123macmini.com/accessories/guide/enclosures.html) with built-in Thunderbolt connectors, or at least cable guides. They could be styled in the same style as the Mac Pro. Imagine just slotting on another level of your little accessory tower, with a single Thunderbolt going to the "capital ship".