Wacom Tablet Multitouch
For the past several months, I've been experimenting with using multitouch for live music visuals. Scroll down for some examples of this in action.
I spent a while trying to figure out the best input device to use for multitouch. I tried iPhone/iPad, Roli Lightpad, etc., then eventually discovered that the Wacom tablet has excellent multitouch. It's not a very publicized feature -- I couldn't find any software that can access the data directly. So I developed a C++ app called Tablet to OSC that accesses the data and sends it over OSC, so it can be used in other software like TouchDesigner.
I created this tutorial that explains how to setup up multitouch in TouchDesigner, both with iPad/iPhone and the Wacom tablet.