One more crazy idea… so that it does not become patentable.
Done 20+ times in Europe including London 2006, Paris, Warsaw, … with slalom windsurf boards using noisy giant fans.
Can efoils attract the masses with silence and simplicity ? Teams and champions are still to be found…
Dull wing tips and short masts needed in order not to damage the pool linen.
Pool design by Laghetto, Milan, Italy, a 30-50.000usd€ item, fixed width (30-35m) but adjustable in length : 60m - 70m - 80 or 90m with zip panels (see below).
Are you in ? 
https://www.piscinelaghetto.com/en/product/pool-design-en/professional
Picture credit: Fred Beauchene Windsurf circuit organiser:
