Modify GS2 for Event Usage

Looking to create an interactive digital graffiti wall using this software as painting app. Easy to make the interactive wall with a projector, a wiimote and a infrared pen with some software that's freely available. Check out wiimote whiteboard on youtube for links of how you can do it https://www.youtube.com/watch?v=QgKCrGvShZs

I'm a complete n00b to this program and forum... but I'm interested in finding out just what mods are possible with this application. I understand it's possible to make your own surfaces and install them to your offline program - Does anyone have a tutorial that they can post details of? I can get a friend who's a director programmer to look at this too hopefully.

Is it easy to get hold of your final image - or does it have to be uploaded to the website?

Sorry for all the questions - give a n00b a break