An interesting interview of assisting ISAF advisor was Johnny Heineken, who is the current Kite Course Racing World Champion:
"While we were there to test racing formats, on a basic level we needed to prove how high performance we really are.
Most people still think of kiteboarding as a sport that needs 15kts and up just to sail upwind, and many of the ISAF folk and sailors were of this mindset. In our own little world we know that we are some of the fastest craft on the water. If I am close to keeping up with Jimmy Spithill and the boys on their AC45 on San Francisco Bay, I can sure as hell knock the socks off the 49ers and Tornados.
We proved this in all wind conditions, sailing laps around the skiffs and multihulls at the trials in everything from 6kts and up (to give you an idea, we were reaching at over 25kts in 7-9ks of breeze). Higher and faster was the name of the game, and everyone noticed, including the ISAF president who spent much of his single day on the water learning about the gear and tactical side of kite racing."
Source : http://www.sailingscuttlebutt.com/news/12/0403/
So, it looks like that racing kites are indeed capable of doing almost 3x the wind speed and can challenge an AC45. Hats off, that's quite impressive I reck'on.
PS: the Swiss won the cup twice but made a wrong choice at the end and lose it. Fair enough. I'm thrilled to see the R&D going on about rigid sails and foils and very pleased to see the action and drama with the AC45 world series. So, I'm sure the AC72 match racing in the San Francisco bay will be fantastic to watch from 5 to 35 knots of wind !