Relatively old news now but a number of kiters have now done official 50 knot runs over 500m in Luderitz:

www.speedworldcup.com/home/index.php

A lesser known challenge for the speed record (amongst windsurfers and kiters) is also going well. L'Hydroptere is a proper boat and achieved a peak speed of 52.86 knots on Sunday. There is a good video on the official website:

www.hydroptere.com/_en/galerie-videos-hydroptere.html#centre

I have a feeling that the kiters will soon lose the outright record too!