Originally Posted by
Necromas
Two natures does not equal bloodline, but you CAN have a bloodline that makes it extremely easy to manipulate two natures into one. Bloodlines can do plenty of other things too though, like evolve an advanced eye that allows for the use of special dojutsu. And I'm pretty sure you dont need a bloodline just to manipulate more then one nature, I mean, look at the Hokage, he combined earth and fire jutsu (combined a fire spitting dragon and a mudslide to get a dragon that spat balls of magma, or something like that) and I'm pretty sure he didnt have a unique bloodline limit, not sure but I also think they said the hokage was a master of all the elemental types, not just one or two.
P.S. If you didn't catch it, Naruto is porbably the King, because being a jinchiriyuki (no clue how to spell that) makes him the most important to protect,
P.P.S. Also, on the colors of chakra = elements thing, I'm pretty sure that all the chakra we've seen in the entire series is blue except for the kyuubi chakra, so unless everyone is the same element as Naruto, which we already know isnt the case, the color doesnt matter to the element.