Perhaps make you own using diabetic chocolate (those made with sugar substitutes like maltitol). Most chocolate (even dark) will have some sugar content, but your best bet is something with a sugar substitute. Hershey's does make some "sugar free" chocolate chips if you can find them. If you have the brand someone in a store perhaps could locate them easier.
http://www.walmart.com/catalog/produ...ct_id=10312014
I am assuming you are going to use them in something that doesn't require sugar....