I could see where this could come into play in a different way. Not a full tank... currently we see the resistive and capacitive type of touch screens, if we make very thin films and put a very thin layer of water between them, and with the right design, it could make for one of the best feeling, most responsive touch screens on the market. I'm not sure if that is where he is going, but it could lower the cost of the electronics of the touch screen and give better results... Its first use would have to be in 23 inch monitors where they could use a type of web camera to view where the disturbance took place... now it wouldn't have to be far back, using math, you could make it very thin, like the side LED lighting system and work from there.
Thats just my guess on how this crazy idea could lead to an actual usable technology.. but who knows....