Mate get yourself to Port Stephens (NSW) on the January long weekend and we'll lend you a board and rig for the national Windsurfer One Design titles; if we get someone from SA we'll probably have sailors from every state.

You can race against Jessica Crisp (2 time PWA world champ, Aloha Classic wave contest winner, 3 time Olympian), Stu Gilbert (4 time world champ, ex olympic team), Dennis Winstanley (perennial Windsurfer champ), possibly Lars Kleppich (Olympic medallist, Olympic class world champ), Wazza Holder (masters wavesailing national champ), a couple of other dinghy and skiff world champs, and have a good race in the Youth or under 15 classes.
For less experienced sailors there's a "silver fleet" where you can race against other people with similar backgrounds - but it's mainly just about the sailing and the hanging out on shore.