You could try tgbuttons.com TG Buttons Home Page
. They have what looks like the same flip flops as in the picture of your bow (search for "sandals" or look under Summer on the menu). Six pairs of sandals in various colors (12 shank buttons total) are $1.89. I have ordered buttons from her before and she had prompt shipping and charges only $1.99 for first class shipping ($4.99 for priority, $2.50 for Canads) - flat rate no matter how much you buy.
Sorry, I don't know how to make them but I bet a Sculpey artist could do it.