Hi DakotaQuilter:
I don't think you'd need batting in your tablerunner if you are using flannel. Using 2 layers of flannel will give the tablerunner a good weight/body without the bulk. Recently I took a class on making rag quilts and for the bear, dog, kitty quilts we used 3 layers of flannel so we had a nice "fringe" all the way around the quilt. This made for a heavy quilt but sure gave the edges of the bear a great look...I think you could use 2 or 3 layers of flannel and not worry about batting. If you layer your flannel blocks and sew 1 inch seams (the fringe) all around the blocks when sewing the blocks together I don't think you'd need the "X" through the block...especially since the tablerunner isn't going to have rough treatment like a quilt might have. The tablerunner will be laying flat on a table whereas a quilt is on a bed and gets wound around body and legs and gets pulled and tugged on.
Feathers