Hello Jeremy -- and welcome to the Forums! The narrowest Airstream product was the 7'6" wide Minuet of the 1970s. Older Airstreams are nominally 8' wide, though my Argosy is closer to 7'10". Airstreams over 22' became 8'6" wide in about 1993-1994. Travel on your roads and with your available tow vehicles will be problematic. Do I understand correctly that waste dumping is handled differently in Europe? So there may be more issues than just electrical. Structural issues with older trailers can take huge amounts of time to set right, but one can be proud of having a classic well before the job is finished.
I've seen websites of various enthusiasts and resellers in Europe. Wonder if anybody else has those? Or Google... There is also http://europe.airstream.com/