There are lots of options in wide backing but be sure it needles good. a company SewBatik has some wonderful batiks in a softer fabric and hand quilts really well. However, if you want muslin look or bleached then the wide muslin is also good It appears that the wider fabric is always easier to hand quilt than the same patterns in 45"
Thank you to the one who mentioned The Stencil Co. I designed the preprinted wholecloth they sell.