I'd like to say Teddy Roosevelt, but I think he's a classic DBA. Strong willed, a bit of a bully, and pushing things through with a sheer force of will at times.

However, after reading Team of Rivals, about Abraham Lincoln, I think he might be a great one. He worked with disparate elements in his own party, bringing them into his cabinet and getting them to work well together. He maintained his agenda, doing what he thought was right, and worked to help others understand the path. Even sometimes letting them argue and make mistakes within the context of his administration and learn on their own.