Looks like you could easily make a duck by gluing some of those plasticy body-wash things to some sort of gully / gutter. I've never used a towel, but it seems to me that once a towel gets wet, it may as well not be there at all. Maybe sew some of those body-wash things onto a towel, and fasten the towel to some sort of drainage along the bottom. The material on the Duck looks fairly similar to those body wash things, I'm guessing that you could fabricate one of these pretty simply.