Instead of forming a bond with a dragon why not taming them like what you did with Odahving (how the hell do you spell his name). The dragons bow to those with a stronger voice then them so why not? This way it won't contradict the lore too much. Say you took control of the Blades and you reform them, educate them in the way of the voice and those strong enough can go find themselves a dragon and win them over. But of course you'd have to have extensive knowledge of the voice in order to teach people so why not go to the Greybeards and say you want to follow the path of wisdom. They'd teach you words you don't know and send you on quest to retrieve lost words, with this you can add to the the collection of already existing words. After you've learn all you can, you leave High Hrothgar, kill the Greybeards or whatever and seek out whoever is in charge of the Blades and take over, revive the Blades with a new goal (maybe bringing the remaining dragons under control and use them to bring everlasting peace?) and start recruiting. Those who do not agree with your ideals will form an apposing faction. With word of your actions spreading throughout the land, all the factions of power begin to worry and start trying to form alliances with you. You can choose to assist one side, remain neutral or take aggressive actions. As for battling on top of your dragon, why not make it so that your shouts have debuffing or buffing abilities, you can weaken your opponents and strengthen your dragon's attack and defense. And let's not forget magic.