Longarmers have different sized frames, but the most standard seems to be 12 feet, or 144 inches. Not all of that width can be used by the quilt, since the sewing needle can't get to the very edge of the frame, and the backing needs to be several inches bigger than the top in each direction (the definition of "several" being up to the longarmer, but usually 3-4). Some longarmers can deal with quilt dimensions being a long ways "off" and some can't. You really need to ask some of these questions of the longarmer who is going to do your quilt, and ask to see pictures of their work.