Overseas shipping
Dan,
We have shipped several RVs overseas to people, including a couple into Australia. The process really isn't very difficult. Your part is actually very simple. Just sell him the plane as you would to any buyer. Australia is one of the simplest countries to export an RV to as they accept all RVs for import, so there's not much for the buyer to do either. Because it's an experimental, he isn't required to have an export annual inspection done or an export Certificate of Airworthiness, like with certified airplanes.
If he's serious about buying your plane, have him contact me and I can tell him what he can expect, and we can even handle the disassembly and shipping for him if he doesn't want to arrange everything by himself.
As for your part, just make sure that when the plane is disassembled for shipping, you keep the FAA registration. It is your responsibilty to make sure that you sign the back of it and mail it in to the FAA. There's a box on the back you check that says the airplane was exported and reregistered in another country. That's it, you're done.
Feel free to call me if you have any questions.