Off the top of my head, I nominate the 1973 UK (Euro?) spec 240Z. It has different front turn signal locations, front spoiler (and rear view mirrors? or are they after market?)
eg http://www.rigsofrods.com/images/imported/2013/06/datsunLarge-1.jpg
And delete Z BAIT and replace it with Big Sam Its more famous.
and swap : 10. 1973 North American 240Z with T-top and maybe another accessory (T top was not a dealer or factory option, and was not available by 1973 due to the company going bust, and the owner having a heart attack. Only "several" cars has these fitted)
with an Aussie spec 240z (1970 to 1972, as they had no side turn signals or rear side markers eg:)http://museumvictoria.com.au/collections/itemimages/146/124/146124_large.jpg
Also, if you had all the cars pointing to the right, instead of the left you could show the differences in petro flaps. Some had door style locks, some just had finger tabs, some had these: http://thumbs1.ebaystatic.com/d/l225/m/ma8IMboL2vC21lLLo8ZX9Ng.jpg
On second though, maybe not. You've already got a hard enough job getting all the different model right.