Since the sharp bend in a foldable is a weak point, what about a roll-up display (rolls into a slot in a tube)? Pocketed, it might be mistaken for something else, but some who feel inadequate might take that as a plus. A much more compact version of the "globals" (portable communications/location/computer device) in "Earth: Final Conflict" gives the general idea. Or maybe it could be in the form of a stylish vambrace (forearm guard) with a retractible screen, which would avoid the particular misrepresentation issues previously alluded to.
Alternatively, what about a weightless unisex purse that exists mostly in another dimension and carries as much stuff as you want, with a "fetch" function to get a particular item out of there without digging through the contents. Diane Duane's wizards, and much later Rowling's (esp. Hermione) had something that behaved more or less like that. There are a few technical issues with having the weight and bulk be ignored while transporting easy access with you, but this is Apple we're talking about; they'll eventually figure those out.

Laws of physics must not stand in the way of elegant design.
But more likely in time IMO would be something like Google Glass, but with the screen as a variable transparency overlay (allowing either AR or VR) , earphones in the temple bars, and EEG pickups. It'd take a little practice to move your virtual finger around with your thoughts, and making it sleek enough not to look like a dork when wearing it would be a challenge, but the tech required is mostly incremental on what we already have. The display would have to go transparent in case of power loss or crash though, so as not to be a hazard; requiring physical alpha and backlight channels.