I saw on zpacks page that they make a bathtub only. Bear Paw wilderness designs sells them too. A little on the heavy side though. I think I can make something out of my Tyvek ground sheet that will work. Also I notices since I have a SMD Deschutes plus I can run the tyvek a little ways up the bug netting which creates a bathtub effect. I wont know until I camp in a good down pour. For those who dont know the Deschute plus has bug netting around the edge