raggy quilts come out GREAT using a regular cotton top and flannel back...i've made them with flannel for the batting too. i've used regular cotton batting, and i've made them with no middle layer...they all come out great...
and for raggy quilts (i've made and sold 50+ of them) i have NEVER prewashed any fabric used. i do not pre=wash the flannel or the cottons. i do stitch a cross (or something) across each block before construction. I have never had one come out weird shaped or funky from inconsistant shrinkage...or any other issues ... mixed fabrics flannel, cotton, homespuns really make great ones.