Something like this is not possible. As I mentioned previously, the closest you could get is two clients running side-by-side (perhaps on separate monitors, for a better experience) on a single pc. Running several wow clients at once, logged into several accounts, and controlling them at the same time is what is known as multiboxing and as far as I know, Blizzard has no problem with this. Read more here:
http://wowpedia.org/Multiboxing
Hotseating, as shown in the picture you've produce, is not possible. The game is simply not designed to be able to handle more than one character controlled in a single client, nor more than one account in a single client. Your only option is A) have several clients open on your PC and multibox it (you could ofc use a controller for one client and keyboard/mouse for another), or B) two PC's next to eachother.