Sorbee's also has sugar free syrups. Maple, Chocolate, Strawberry and Blueberry. I haven't seen them in too many places, I originally found them at Sick Kids in Toronto, but just got some at Hy & Zel's drugstore in Oshawa. I heard they had the chocolate at A&P in Whitby too. Lots of stores carry Sorbee's products so maybe you could ask them about the syrup. Also at Hy & Zel's they had Sorbee's jam type spread - strawberry and grape.

Sweet'n'Low has a sugar free chocolate syrup too.