I met a young man today in Wagga riding one of these things...and all I can say is I WANT ONE !!!
Of course, I pinned him down and demanded some answers
Basically if you want one, you have to build it your self. But he told me that it is expected for the first commercially produced ones to be on the market this Christmas. He said you can buy them on line now, but they cost about $15,000 (Aus). But he made his for about $700.
I should have asked his name, oh well...He got a second hand surf board on ebay for $100 and the foils direct from China for $200. He used a 3D printer to make the motor housing. He is using a 700Wh battery bank (@ 50 volts) which is about (actually it is exactly) 14Ah. He gets 20 to 30 minutes run time. He said he is building a new battery box with 2000Wh battery bank (40Ah). His motor is from an RC airplane with a small 3 fin boat prop.