I agree with NJ Quilter that Moda flannel is about the nicest I have ever worked with but I have never seen it wide. It is so wonderfully thick and lush and it has never pilled on me. I do have a wide flannel backing from Sew Batik that appears to be the same quality as Moda. But it has been in my stash for years waiting for a very special quilt and now they have discontinued their wide back flannel. Plus I have never washed it so I don't know if it will pill but judging by the quality of its feel I would be shocked if it did.
I ordered a wide flannel once from thousands of bolts and was very disappointed in the quality of it. Thankfully it was a remnant and I never intended to use it as a backing.