You've had the option of attaching external storage to the PS4 for a while. If you find the existing options just too gauche, though, you're in luck. Seagate is releasing an officially licensed Game Drive that brings 2TB of additional space to your PS4 while matching the aesthetics of the console. It's ultimately a standard portable USB drive with a PlayStation logo on top, but that's not necessarily a bad thing -- it's still an easy way to add extra room for games (roughly 50 more, Seagate said) or cart your library to a friend's place.
The Game Drive promises "full-speed" gaming comparable to what you'd get from the PS4's internal hard disk, and supports any PS4 using at least firmware 4.50 or newer. It'll reach North American shelves next week for $90 ($120 Canadian). That's roughly on par with what you'd pay for a typical 2TB portable drive from Seagate, although it's not the most affordable option if you aren't particularly fussy about branding or physical dimensions.