Personally, I wouldn't recommend it. Not only will acting and SMing at the same time present problems during the run of the show (like your concern about how to call the show), but also in rehearsal (taking blocking notes, for example).
Besides the practical issues, I tend to see the SM and the actor as two separate entities who have very specific jobs in relation to each other. In my experience, combining the two roles can lead to conflicts of interest -- for example, it's hard to remain neutral in a conflict between the director and an actor if you are also an actor.
If you do decide to take on acting and SMing, kmc is right - have a talk with your director about it first, and make sure everyone's on the same page.