With 6" we are at the limits of what the stock setup allows. Yes, the draglink (relay rod) is at an angle and the truck does have some bumpsteer. However if you drop the relay rod, then you have to drop the panhard rod as well. For 10" you would have to address it.
No-one makes hi-steer arms (OK some crowd in Canada does, but not at a realistic price). So for now we have to live with it. It is not bad, Sean just drove his truck from CO to Canada without issues. Any taller, and you would have to go custom. Brad (with the big 10" lift) has actually dropped his truck down a little with new springs that he got from us. Also, the whole suspension on that truck was custom.