I'm no royalist, but even I know that Scotland does still have a royal family; the same one England has since 1603, though it's been the royal family of Britain since Queen Anne in 1707.
However, if you mean it more as Healthfield has interpreted it, then it's very difficult to say if only because a look at the genealogies of kings and queens reveal that they rarely stay within one house for long.
Oh, and if you take the Jacobite view, the current king of Great Britain should be Franz, Duke of Bavaria!
http://en.wikipedia.org/wiki/Franz%2C_Duke_of_ Bavaria