Insulmat...it is a warm, inflateable sleeping pad, a bit pricey but seems to be a sturdy item.  I used one of these a friend had and was sold, and purchased one for myself.  Another idea from Solotripper: Use the waffle anti-slip sheets sold to pad dish closets and keep dishes from slipping on the shelf to keep your nylon things from slipping out from under you.  I thought that was a GREAT idea!