Yes on Green Card for US license
Wheatwacker's comment: "The question he asked was, can you cover a bike purchased in Europe with European plates ridden by a us licensed rider."
I bought Green Card insurance from Doug and Polly last year for my bike which is registered in Ireland (thanks Wheatwacker!). I'll buy it from them again this year, too. The only problem is that this insurance is no good in the country of registration (Ireland for my bike) .
Last year in Spain (Cataluna) I had to show my Green Card and license to the cops. No problem - they checked the insurance, registration, my CA license and International Driving Permit and we had no problems at all. This was about parking in the wrong spot - we just showed them all the papers, smiled, moved the bike and spent the rest of the day on the beach.