Personally, I think we're in the midst of a Sandman bubble. They've suddenly become popular and to begin with were well priced but the nostalgia factor has kicked in and prices are at a pretty high level for what is basically a commercial vehicle with a sticker kit.

In my limited research it seems Australian classic car fads drive up prices slowly and steadily till they drop suddenly, quite often due to outside factors (economic etc).

The GTHO values have taken a hit, as have HDT's. Watch for Monaro's to dip as the nostalgia buyers get older or the stock exchange tanks.

I think the prices are unsustainable for a non-performance vehicle that was mass produced and production numbers can never be absolutely known