Amazon is currently listing the 20th Anniversary Dualshock controller for the PS4. It is in the style and original grey color of the old PS1 controllers. It is available as a stand-alone purchase, meaning you do not have to buy it with a system.
The item is available for pre-order now, and will ship on September 30th, 2015, when it comes out. This item is expected to sell well, so you might want to grab it quickly.