When flannel was mentioned, it wasn't flannel batting, but regular flannel instead of batting. It actually works quite well, with the top fabric, the flannel in the middle and the bottom fabric - all are cut the same sizes, and it makes each block 'rag' a bit more. I actually prefer using flannel for rag quilts. I saw a product on line that may help you:
http://quiltersreview.com/index.php/...safe-and-easy/
Enjoy making your rag quilt!