Some of the Clarkes shoes outlets in Bangkok used to sell childrens shoes but it seems they have all stopped stocking them - Central Rama III used to have a good range.

Does anyone know anywhere which still stocks them?

I am not sure about clakes but you can find Ecos (Sp) in the Phuket mall

Not much use, but Central Bangna had a limitted selection, not widths and no sizing measureres but they had the shoes. IMHO Ecco are the best bet, they last longer and are cheaper.