I'm guessing you'd have to use some sort of program that watches MC to see what it's doing and kicked off a message to Event Ghost. The SDK appears to make it possible to do that. Register for events and catch them when they're fired off.
I, too, am interested in more robust integration of MC with other equipment. Mainly as a way to provide audio to a whole-house setup. Right now most programs only 'scratch the itch' of one or two approaches to the problem. Something like a plug-in for Event Ghost might have interesting potential...