Why? Seems to me just getting an external thunderbolt hard drive and plugging it in would be cheaper and easier thant having just a display with one in it.
Has anyone ever made a display wiht a built in hard drive (USB or otherwise)? Seems to me if there was a demand or desire for it, there would already have been such things long ago.
Far easier to make displays with just ports, then let people plug whatever they want into them as needed.