It might have to do with government restrictions on devices that can be used for targeting people – the Panasonic GridEYE is considered a “controlled device” here in the USA. I was going to do a product based on it (i.e. it can tell you how many people are in a room) but the usage restrictions made it too difficult to sell.
So, I just open-sourced the project
http://bit.ly/1clb03r
and people can build their own if they want to try it out.