One of today's article reminds me this Coanda effect flying saucer. Instead of using four big rotors, it uses only one smaller and require a lot less power to fly.
One of armature developed a web page: http://jlnlabs.online.fr/gfsuav/index.htm
There are also a company try to develop it into reality. http://www.gfsprojects.co.uk/
Youtube video if you want to see http://www.youtube.com/watch?v=DW0cgBoWGVM