It is a common criticism from PC owners that Apple lacks a mid-range desktop which is expandable and upgradable to some extent.
Maybe as Apple is going all-guns for market share and bending over backwards (such as Intel processors and Boot Camp) to attract Windows converts, they're considering it.
The iMac of course is conceptually a whole, an entity in itself - and very good because of it. And physically smaller, or thinner, because it's lack of free space and easy accessibility.
So wonder if Apple could retain it's integrity, constrain its dimensions and yet attract PC owners who have often upgraded or expanded their computers once or more?