My Bike Friday packs into a suitcase that meets airline standards. You can find the dimensions on the Bike Friday website, and then use those dimensions to compare to your own suitcases. I don't know, however, how much disassembly would be required for a Dahon or Ubiquitous Chinese Bike.
If I were as lucky as you are to spend the fall in Seville, I'd just use the Sevici bikes. Less hassle, and you still get to see the city by bike.
http://www.sevici.es/