Tractor restoration is a well developed field with mostly older restorers. Early tractors can be surprisingly expensive if the model is sought after like the Lanz Bulldog. They have been bought up by European collectors. There were imports of small consignments of unusual brands in the period of shortage after the war so it's not impossible there's a 1950's Renault out there waiting for you. In the 1980's Zetor Australia found a late 1940's Zetor that had been imported into NSW and sold with a box of spares (including a cylinder head). The apprentices at the Port Melbourne plant did a very nice restoration. But if there is an early Renault about chances are you will have to pay more for a rusty pile than a going smaller tractor like Shane's.