You want protection against what? Some "covers" are protective only against dust. From even a short drop you hear wood against the other object. The little soprano Kala in a case came from Scottie's Music in Hawaii. The padding is the lightest weight foam made but does stop hard contact between uke and a flat surface. There is a thicker piece across the bottom for when it is placed vertically. The stuff recommended above for head liners is also the stuff for dashboard covers. It cuts nicely with scissors. Were you to make a bottom and a side strip, you could create a nicely padded little case. To mate the two into a one piece, just a few here and there LIGHT dabs of silicon rubber from a tube would hold the edges together. One does not need full joining all the way around as you get with sewing. {Do it on the sides which contact the case so there is no show /no contact with the instrument. Yes... small sections of masking tape or Scotch tape will hold the pieces together. It does not need to meet USPostal standards. I do not use nylon fleece of any density because of stuff that can get into the fibres and scratch the uke's surface. I don't want to have to vacuum out my case for cookie crumbs, etc. Go see one of your local upholstery shops. We don't call it scrap....rather it is random sized pieces that will be still useful for such things as what you need.