Actually, I feel a bit ridiculous posting this, but it's not fun having a freezing belly. So I just cut up one of my old sweaters and now have a cozy wool belly band. :-P Plus leg warmers from the sleeves. Jason told me I look ridiculous, but I'm pretty used to that by now....
I thought maybe I could felt the end of the sweater I cut off, but it sounds like felting requires washing the whole sweater and drying it. But look at the cool things you can do with felted sweaters. Maybe I can soak the end in hot water and then try ironing it dry? I'm sure that will smell horrendous, but might work.