I use a thick navy linen with a homespun texture, with a pale khaki twill for the lining and soles. The elastic was actually salvaged from the "shelf bra" of a camisole (seriously, when will clothing manufacturers realize that an extra layer of fabric with a band of elastic does NOT constitute a substitute for a proper supportive undergarment?). It's thick and slightly fuzzy, and worked perfectly.
Hopefully these fit the little chap they were intended for -- otherwise, I'll get busy stitching up a slightly larger pair! My babies had such tiny feet that I can never get a good sense for how big baby shoes should be. I have a feeling I'll be buying the pattern downloads so that I have access to all of the sizes that Leisha has designed. I love the style, and think they're perfect for little ones!