Building a synchronous connection with a SME into a Storyline course

Does anyone have any experience with building functionality into a Storyline course that allows a learner to connect with a SME in (almost) real-time? I've seen courses use discussion threads, which is great, but the asynchronous nature of a discussion thread means that a question the learner has will not be answered within the window of the "teachable moment." I'm thinking of functionality similar to a "live chat" on a website. 

Naturally, there are a lot of variables at play here (SME availability, how SME(s) are notified of a question in a timely manner, how the student is notified when their question has been answered, technology that facilities all this, etc.), but I'm just looking to hear if anyone has any experience implementing or facilitating a solution like this. 

Or, if this is something that just sounds intriguing to you, is it something that you could see being implemented within your courseware? What limitations do you think would keep it from being successful?

Thanks in advance for sharing your opinion on this. It's a solution that I'm exploring and I haven't seen anything like this in the e-learning market. 

Erich