@vrijegeest came up with a very similar concept back in the day, even before we had iPhones.
Amplify’d from itunes.apple.com
nonlinear allows you to design and present non-linear presentations. You can practice your presentation or display it on an external monitor. You can navigate to any slide without distraction using a visual matrix, move a presentation in infinite directions smoothly, record the audience’s input, and be more convincing. Read more at itunes.apple.com
See this Amp at http://bit.ly/btKkrR