There is a tape at Joann's that is for piecing batting. I have never used it. I keep my pieces of batting for rag quilts. Also there is bag patter by Aunties Two that calls for strips of batting. I made a small bag and I will be making the big beach tote when I collect more long pieces. From all the bags I made that one gets the most compliments. It is called Baly Island Hobo
http://www.auntiestwo.com/pattern.html