Remember the XM and XP Falcon Squire wagons of the 1960s with their fake wood-grain panelling? Aussies loved the bush but not many could see the appeal of carting it around on the sides of their cars. Or the R series Valiant with the fake spare wheel carrier on the boot-lid, which most Aussies saw as a spare toilet seat.
And size was another issue. Remember Ford's 1959 Fairlane which quickly earned the nickname 'Tank' because it was just too big for most pragmatic Aussie tastes? Chrysler also learned the hard way with its bloated and heavily US-influenced 1971 VH Valiant range, showcased by the poor-selling two-door Hardtop which looked enormous and never stood a chance against the 'Aussie' Charger.
Can you think of other imported automotive ideas (not just US either) which never really caught on here?