Thought I'd share my process to quell some of the misconceptions about bringing in a car, and run through the general process for the newbie, at least as of earlier this year.
1) Finding a car overseas: Don't trust what the seller says. 90% of US cars are junk - and the ones I was looking at were in the warmer, drier climate areas. Ask the seller all the hard questions, if it sounds ok get an inspection, and wait for a good one. Be under no illusions... the US is in trouble and theres plenty of good cars for reasonable money. Also, do not buy from Chic's Corvettes in Las Vegas. Corvette Mike in LA isnt a bad joint, although priced above private. Corvette Lady in LA i found very expensive for the metal and cars of varying standards. The cars are well advertised and look good value... but are mostly polished turds.
2) Importing the car: Bet on $3500 for shipping with an agent handling it. It was a very simple process; get the car to the agent's location in the US, pick it up 3 months later. Just make sure you have your paperwork in order before submitting to the Australian govt. Importantly, obtain a bill of sale from the seller, even though its not legally required in the US. Note that the processing time for import approvals is not 15 days as stated; its running at around 45 days at the moment. You'll be billed your GST and fees on top of the above costs.
3) Getting the car on the road. This is the main reason for this post, as a lot of the prior information is inconsistent. You need to get the car from the docks to your home. I paid $240 with Toll to get the car from Newcastle to Sydney (others quoted up to $660); it took 3 days somehow but the price was very reasonable considering it avoided the RTA hassles with unregistered vehicle permits etc. For a '72, all you need is belts, headlights, and passenger mirror. Belts - I'm too useless to install but sirfixalot on this site did a great job and i was happy with the outcome. The lap-sash belts were a bit more expensive than i expected after reading up on the prices of the lap-only belts. Headlights are available at Repco for $30 a pair, and take 15 minutes to change over. Mirror just requires some slow drilling and installing the lugs. If you are buying a mirror overseas, make sure you buy a mounting kit for the extra couple of bucks. I sheared the lugs straight off while trying to screw in as the bolts were too short and the rubber was crap (thanks Ecklers!)... and spent a day running around trying to find new ones. After this, took it for the weighbridge and blueslip mechanic where it passed without issue. You can legally drive it to the nearest blueslip mechanic and the weighbridge without rego. Dont take chances though; call in advance and tell them you're coming to cover yourself. Engineering is not required for LHD registrations. RTA are clueless when it comes to registration. Just make sure you take some proof of ownership ie copy of US title or insurance, the original import documents (which they kept??), and all the normal documents. License plates fit easily in the end, just drill a hole and bend to shape, not nearly as big a drama as i thought it was going to be.
All up, its not a hard process. Just get the right car, get your paperwork in order, and you'll be right. Driving on the left hand side is very very easy. Insurance is cheap as chips if its your second car, but be prepared for spending more than you expected to get it on the road. Also... they drink the fuel. Rego is pricey as its in the top tier weight-wise.
Do it!!