New cables and new brake lines? When buying new bars, a rough formula to follow is to measure the increased height + 1/2 the increased pullback that the new bars will give you. This amount will be very close to how much additional cable and brake line that you may need. However, the best method is to fit the new bars to the motorcycle and then make the increased length determinations, if needed at all.
Additionally, make sure to allow room for your new bars to clear your gas tank on full lock turn.