I've been interested in attachment chain too but I can never find any that's easy to get my hands on. Most places only sell single links which can get costly if you want 40-60. I've thought about China but never sent any enquires. Here is one factory that says it does mininium quantities of 1m but I'm not sure how believable that is. http://www.alibaba.com/product-detai...037354102.html
Let us know how it goes because I'll be copying.