Recently at the IA Summit in Denver, Colorado I had the opportunity to present several months worth of research into the myths and assumptions behind multitouch interfaces. Distilled down into a few key points the poster seemed to be well recieved by everyone who stopped by. I am now posting it here for the world to see in the hopes that it will continue to spark discussion and debate.
A study in two-handed input by Buxton, B. and Myers, B.
Two handed virtual manipulation by Hinckley, K., Pausch R., et al.
Integrality and separability of input devices by Robert, J. Sibert L., et al.