'windsurfing rental'
I heard of that once, about 1992 I think.
Lots of great places to sail,
Zippo in the rental thing north of brisbane.
You might be better off buying an old crapper to take with you but Brisbane would be the best place for that.
There is bugger all in the way of windsurfing shops north of sunshine coast(Northern Brisbane)
Or put a wanted add in the seabreeze classifieds for "old windsurfer" in Rockhampton,you might get lucky.
Remember to call into Bowen on the way up, one of the best windsurfing spots in North QLD

Oldschool meaning blasting and gybing on a freeride board less than 100 litres! Newschool,for me, equals freestyle and waveriding.

If your in Rockhampton, head to Yeppoon which is 30mins away. If there is good wind around there will be a few of us windsurfers out on the water, we are always up for a chat. Ask for Mat, the 'Tall Guy' and the other windsurfers will know who I am. Unfortunately I can't help you with any hire gear though.