Ruben, don't bother with Audi camp, pilots don't seem to go there any more. You should go to Sedia or Motsebe for camping. Or if you would rather, for P100/ night you can get a room at Alfa Accommodation with a bed and fan.
Tents are definitely available here in a wide variety of sizes/price/quality. If I had my time again, I would probably have buy a tent in Maun and use the extra few kg of luggage allowance for other things.
I'm afraid that I can't give specific details about the Airvans, however I know that a couple of guys have been to Luxembourg to fly one. I also understand that there is at least one in the UK.
An American guy looking for work earlier this year found one for hire. He's from California. He posted a few pages back under the username Daman. Perhaps you should get in touch with him.
Good luck and see you next year.