How to create an MMO? (this ones different)

Yes, I know this question has been asked many times. This time is different though. I am part of an Indie game company named "Overcast". All members of this company have working experience in Unity. Now this company is freshly started. We have created test games and they are smooth. We know what we're doing. So, we thought; can we take it up a notch? We've been discussing, lore writing, brainstorming, creating characters, etc. Now we just need to know where to go with this. Now we don't want an in browser MMO. We've looked into SmartFoxServers. What can we do to make this happen? What can we use with Unity to make this work? I won't appreciate any negative comments regarding this. I appreciate anyone who comments something constructive. Thanks guys, ~ghost