Way back in 2009 I spoke with a chap called Riccado at Solari Udine who gave me a approximate quote for them to build my project... €40,000!!!
However he was kind enough to provide a PDF diagram which was interesting, and a photograph of that particular unit in production which as it turns out was installed in an American University Library to show some of the Google search strings of students in the library (filtered of course).
He also provided a word document of how the display was controlled which was based on a PC running a small web server application which acts as the interface, like any modern web API really.