Why don't you just do the masks instead?  They are free, and you get a stamp and something to add to it (bead, construction paper, item, etc.) at each country. I think they actually make a better souvenir, too.
Here's a small tip:  You know how Mom ends up carrying everything.  When the mask is finished and inevitably handed to me, I go to the nearest gift shop and ask for one of the green bags.  I put the mask in it and hang the bag on my fanny pack.  It's almost like I'm not carrying anything!