I think it's about time to post mine. I'll be rampaging through the Outback in a modified '70 Dodge Coronet. Plans are for something along the lines of the Furious 7 Charger, not as fancy or flashy though. Like last year something a moderately skilled person could pull off. I'm going to try scratching a truck 4x4 frame, if that fails I'll seek out a good junkyard donor or something. Probably keep the 426 and see about making one of those Edelbrock Fuel injection carb systems.
I think Rob's post covers it well enough, near as I have found standard equipment for Australian cars is very similar to US cars. Headlights, tail lights, turn signals, windshields, license plates, ect. I can't say I've found anything restricting paint schemes but keep in mind the flasher it is the more you stand out. I don't think we need to be too specific with rims and tires sizes other than you know, nothing way over sized like Monster truck tires or small rubber band tires. Those definitely wont work out for the off roading part. Something I recommended in the opening post and something I will say again is that Google (any search engine really) will be your best friend for examples of what can be seen on the roads. There's even few road traveling videos, be them long and boring at times they also provide good examples of what's on the road. The .gov link posted was the best thing I could find. I wasn't able to find a simple list of absolute specifics.