one other thing to bear in mind - if you buy a US specific model - say a bike friday, or Xootr Swift, you might be able to sell it at a little profit in europe when you leave. My advice would be to put it on the UK ebay, and you'd need to work out how to handle shipping, but it should be doable (I just shipped a folding bike from UK to Italy).
Both Xootr's and Bike friday's fit in suitcases, btw...