my backyard gathering quilt (shown above) is felted wool applique on a black flannel background- i also used hobbs 80/20 black batting and a solid black flannel backing. the red (sawtooth) border is also flannels. i've made lots of wool projects on regular cottons- but i love the flannel/wool combination- so cozy warm & lofty-
i generally save wool background projects for smaller projects- due mostly to cost & weight.
visit Sue Spargo's website, also Primative Gatherings, The Wooly Lady, A Couple of Sister's Designs, the Cotton Patch Quilt Shop.....there are more-but those are the ones i can think of right now- and the ones i frequent- for supplies, inspiration, patterns, hints, help and encouragement.