Now this is super-sizing! Behold the Pizza-Size Burger from Burger King of Japan:
Wide is what you get with Burger King Japan's 8.8 inch (22cm) diameter Pizza-Size Burger. Note that only the buns are extra-wide, in between are four regular Whopper-sized beef patties arranged in a four-leaf-clover pattern. The fillings and toppings are also normally sized but at least they're provided in abundance.
Don't think it's made mainstream BK yet. And There's probably a good reason for that ;o)