Rachel and I played Puerto Rico last evening, which I won by a bare 2 points.
In order to bring PR to England, I wanted it to be compact and waterproof. To do this, I took only the necessary pieces for two players and dispensed with the boards. The entire game fits into two thirds of a ziplock sandwich bag. When I lay out the buildings and stuff on the table at the beginning of the game, you can hardly tell that anything is missing.
Of course, a deck of cards is a portable and compact boatload of games. But other Euros could probably survive the same treatment. Which leads me to believe that publishers could make portable versions of these games WITHOUT sacrificing the game play, like they did for games like Blokus and Settlers.
El Grande would fit into a sandwich bag if you could take the provinces as seperate little puzzle pieces. Princes of Florence needs only squares for each player, which could be rolled up plastic sheets.
The compact versions of the games would cost about a fifth of their current cost to produce, would fit in much less space, and be portable.