Is there such thing as windmill kites? that would be cool. Big kites that had wind turbines on them. maybe a very low cost method in areas where ground conservation ( Brown-footprint) is concerned...
There is actually a viable design for wind generators that could be considered kites, but balloons would be a better description. http://organicconnectmag.com/wp/2009/12/from-war-machine-to-clean-energy/
Absolutely they exist
Check out this group for all you ever want to know about them. http://tech.groups.yahoo.com/group/AirborneWindEnergy/messages
my video for my design http://youtu.be/tZHn9_qiluE
I have plans that improve it massively so that It if can be made by anyone anywhere for so little cash and be much more reliable.
I also have plans which add tracking, generation and a tail lift, extending kites and the ability to band gang them way high into the sky for serious utility global scale power.
Mu Ha Ha Ha...
luckily it's all open source then