Does anyone ever use a sheet (bed sheet) as backing for a quilt? I need to back a King size whole cloth quilt, and I want a wedgewood-y blue. I've been looking for the right color for two weeks, and can't find what I want - except in a king sized sheet. I did find one, but it's 44" wide. My pre-printed top is 90" x 108", so even 2 of the 44" wide sewed together won't be big enough. Any suggestions? (Nothing on-line. I don't buy on-line) If you can use a sheet, what thread-count?