The best flannel hands down is Killington flannel that is specifically milled for baby items, diapers in particular. I do not know if it comes in wide yardage but I just piece my backs when I use it. It is a very soft, thick flannel and is great for quilt backs. As with all flannels it needs to be washed and dried with high heat to shrink it but after that is very durable with little to no pilling. It does cost a little more than regular flannel but is well worth it. I have been using it for years.