Hi there,
if you are after a case for the mic alone you can do what I did.
Needing a case for a very long mic Sennheiser ME88 I purchased a hard case for carrying fishing rods.
Constructed out of plastic pipe with push on end caps i cut it to length and cut out a foam liner 1/4 inch thich and before glueing it inside the tube I covered it with Lycra material so that the mic with its foam windshield slides easily in and out.
being very sturdy i attach it to the side of my bag.