There were several significant figures who were President of the United States in Congress Assembled (under the Articles of Confederation), John Hancock being the most well known, if not for that reason. Honestly, to get what you are wanting, the entire period leading up to the revolution or even before then, would have to be altered. It is mostly luck and circumstance that "These thirteen united States of America" became "The United States of America" as soon as they did. It would be hard to get the Constitution created before it was.