Yes, mine is two pieces sewn together, with the seam running horizontal. I did get my mesh from thruhiker, same stuff. Each side panel is 72″. The bottom tieouts for stakes are 20″ from the bottom edges, which actually makes for ~1.5 foot extra that can be tucked under the groundsheet. So the seam is usually under the groundsheet. Or, alternately, it can be pitched higher, w/ 2-3 short guylines. Hope that’s understandable!
Something smaller could certainly be made without anything but a ridgeline seam, using the 55″ width vertically. Headroom would just be more limited. I wanted mine roomy for camp chores, sans tarp. Or a vertical seam could be used, eliminating the ridgeline seam. I’m happy with mine, but I’m still open to other ideas.
Another thing I’ve considered is making a silnylon floor which tapers into a bivy-sack shaped footprint in the foot, w/ a 6″ tall, bath-tub style lip all the way around. Mesh could be sewn to that with only a ridegline seam. A zipper could even be added to the head-end (a la MLD bug shelters), but I still think I’d leave the mesh unattached (and longer) in the front and along the front 2 ft of each side, and just tuck that section under the groundsheet. Something like that could function a bit like a bivy, but with the head-end roominess of a groundsheet/shroud. Vertical silnylon or Pertex Quantum head and foot panels would enhance storm protection. Obviously an attached floor would be less suited to bathing and cooking however.
Sorry if all that complicates the discussion, but just thought I’d offer a few ideas beyond my current solution. I guess it depends on how involved you want to make it.