The thing I love about old Southern live oaks is not really the spreading limbs (although they are spectacular), but the roots.
I've been to all these sites and have seen these same trees. What doesn't get in photos are the carpets of exposed roots around them. They undulate like snakes underneath the tree. It's a feature that doesn't usually get incorporated into live oak style bonsai...
Also, the outer lower branches sag so much that many have re-rooted in the ground at their very tips, acting kind of like tethers on an elephant--they're not tropical aerial roots, but similar...