Maybe bloch flats?, I'm a small size 35 EU (4.5 US) and I have a pair of Bloch ballet flats (regular not Fold-up) that run small, they're size 36 and they are like a small size 35.
I know that this pair run small, but probably are too big for you:
http://www.zappos.com/bloch-monique-roll-up-gunmetal