Good thread, thanks. I've got 2 1/2 bikes on the water at the moment... the KTM I rode from Sydney to Laos, a '47 Beeza that I still haven't clamped eyes on (bought it from a photo) and most of a '38 Norton... the frame of which I brought back as my checked luggage.
You raise some interesting issues. I brought the Norton frame home, because the Thais would never have let it out of the country... but all the other parts, no problem. The reason being, no title or rego or import permit for it. It had been (literally) carried out of Burma 16 years ago and if the frame had been there, that's it... pay whatever import duties they deem appropriate - which would be significant. The Beeza, on the other hand was easy - it came into Thailand on a temporary import permit the day before the container was packed.... straight in and cleared out of Thailand. Its registration is, believe it or not, American.... and the guy I bought it off isn't American. I dunno how he got it, but I intend to ask, next time I'm over there.
The KTM was the hardest of the lot. My shipping agent went on holidays and my temporary import permit expired. She was supposed to renew it before she went on leave. They wanted me to go back to Thailand to sort it out, then they wanted me to pay $22,000 import duty.... and so on. I wrote a nice letter to them explaining why I'd had to leave in a hurry, enclosed a scan of a big $ surgeon's bill for a family member, etc, etc... and I got a "oncer" approval for the bike to come out. I reckon they'd have played hard ball without the surgeon's bill.
The KTM left Oz on a carnet - about $1,100 total cost for that for a year. That expired in August, but I was into countries that don't require a carnet - eg Thailand and Laos... so I let it lapse. Instead of renewing it, I got a $50 Vehicle Import Approval for a returning vehicle. If I'd been smarter, and submitted all three applications together, I believe it'd have been $50 for all three, rather than each. The only VIA hassle I had was that they require a photo of the compliance plate. Mine got half wiped out by the tusk of the elephant that attacked us.... the sticker is now two pieces, with a groove up the middle. I got lucky though... all the numbers are on the edge and still visible. I sent them a photo of the elephant standing there with his foot on the fallen bike.
So far, so good.
A man should only do the work that is required of him. To do more is a form of greed.