I bought a bike (1992 XJ900) on eBay in the UK which was sent to a freind's place who stored it. I was in Australia. I then contacted many insurance companies and tried to buy online. Bennets was the only one that allowed an 'international licence'. I gave the UK address where the bike located. They assumed that I was residing in the UK. It was really cheap; full comprehensive for 1200GBP for 87GBP. I think it was cheaper for me as I was 58yo. I used the address where I was staying and I had an international licence. The only problem was that I was not a resident.
We didn't get green cards, just bought insurance at the borders, easy and pretty cheap. The ferry ticket from UK to France worked as proof of insurance when entering Greece.
Once I had the insurance I could get the bike taxed. If I had have had an accident, I'm not sure what would have happened. Did 17,500km from UK to Damascus and back, not even a flat tyre! the trip's on (http://www.newbold-thebigride.blogspot.com
) if you're interested.
The insurance was a means to have registration papers in a name which matched the passport to make border crossings easier. The bikes were disposable, we weren't trying to protect our investments. It was a risk we were prepared to take. Fortunately, nothing went wrong.