Work is underway on 60Ghz Wifi, which has wavelengths of only a few millimeters.
http://www.pcworld.com/article/2030041/meet-60ghz-wi-fi-the-...
In a few years we could have tri-band routers covering 2.4Ghz, 5Ghz and 60Ghz. Correlating the info from all these frequencies should provide a much better picture.