I will check out the Lakes around the Lake Grace / Narrogin area over winter, a lot of them filled 2 years ago with the floods (Cemetry Lake @ Lake Grace had 3 metres of water) and lasted most of the year.
If the rain is good to us this year a few of them may fill again and would be a good race location for something different.
Many of the Lakes are closed to PWC, however if you were to get the local shire support I can't see why DPI would not grant approval for a race event. I will assist in this area if the time comes as I know most of the CEO's is my area.