This sounds like a great idea, as no one has done it in Australia for a while. But you would want to do it properly.
Lanock Motors, the former giant NSW VW dealer/distributor, set up a VW Campmobile rental business in 1971, based from their Camperdown premises. Later you could also rent VW Campers from Lanock Motors Wollongong, and also the House of David at North Ryde. At the peak, around 1976, they had a fleet of over 30 of them. They upgraded to T3 Wasserboxer campers in the 1980s, and the business survived until Lanocks were closed down in 1991. The fleet was down to 6 by then, and was sold off. Today you can only hire new VW T5 and Crafter campers from rental companies like Britz and Kia Campers.
There are a number of places in the UK that hire out air-cooled Kombi campers, and it might be a good idea to contact them for advice and ideas:
http://www.vwcamper-hire.com/
http://www.eastcoastcampers.co.uk/
http://www.vw-camper-van-hire.co.uk/index.htm
http://www.camper4hire.co.uk/
Remember that Australia is much, much bigger, harsher and more remote than the UK, and these vehicles are now at least 30 years of age. Reliability could be a problem unless you take complete control of your fleet's mechanical condition. They should all have new (or recently reconditioned) engines, gearboxes, suspension and brakes. The interiors should be fresh, and in complete working condition. You don't want clapped-out ex-backpacker Kombis that will break down the other side of Oodnadatta.
Consider getting a few modern VW T5 campers for your fleet as well, in case customers still want a VW camper but with the modern road behavior and comforts.
