University of Groningen in the Netherlands have created the world’s largest curved multitouch screen called the Reality Touch Theatre.
See the giant touch screen in action in this video
They used six Optitrack v120 slim camera’s with good sensitivity for infrared light. 16 infrared emitters (as for security systems) and 1000 LED’s are used. A touch detection software runs on three old computers with two camera’s. Extra computer combines the output from the detection computers and sends event data to main visualization system. This way they have processing power to be able to run the detection software at 60Hz and with a latency between 30 ms and 50 ms.
See this short clip cut from a 24 minute lecture about Geographic Information Systems which uses the touch theatre.
And you were impressed with Microsoft Surface Touch Tables.