My 9 cap has heli sliders on the sides, seemed like the right kind of controll for such a devise. Would have to be made up from a lightweight plastic to be practical and weigh not a lot more than a standard servo or in that range to be of use.

As for the Idea, there are very few new ideas, just new applications for old ideas. I figured someone had built one before but with the popularity of the 3d stuff maybe its an idea that could be recyled for the application.