If Intel, GE, or Mircosoft hired a consultant to advise them on the right move, the vast majority of people on HN would scream bloody-murder and speak about it as a perfect example of big-business and its stupidity. What hypocrisy!
Ben, the reality is that you clearly have moved past Steve Blank's description of a start-up; you have found a working business model. Now, the challenge is to find out if that business model is something that can last for 5 years or 50. No one on this board has run a successful company for 50 years. Thus, everyone, definitely including myself, is well out of their league.
However, since entering the old school world of finance, I have realized that there are many men and women who are twice our age who would be able to give you great advice. You need adult supervision and that is OK. You don't know how to hire an executive (i.e. adult supervision). Thus, you should first find someone who can help you find adult supervision. A great place to start is in the 'boring' industries: finance and manufacturing. Find a wise advisor who can help you find an executive to lead.
You are no longer a start-up. Running a post-start-up company like a start-up will kill it as quickly as running a start-up like a Fortune 500.