This is from the same company who made the car Branson drove across the Channel - they also do a nice quad bike/jetski. the company is based in Britain and owned by a NZ and British bloke.
http://www.gibbstech.co.uk/aquada.php
They are soon to open facilities in the USA to target the market there - they are still 2 years away from production though. I suspect building a RELIABLE version they can sell is proving more difficult than first though.