I had the slide on a 75B crack after 30,000 rounds so I went looking for a new one. I called CZ USA and they said they don't sell replacement slides and then the guy told me, "besides, the serial number will be different from the rest of the gun." I wanted to tell him, "In the United States even if you have numbers stamped on every single part the ONLY serial number that legally matters is the one on the frame and if you are a firearms importer and distributor you should KNOW that" but I didn't bother as he probably wouldn't have received the comment well anyway. I just thanked him and ended the conversation. I then went to CZ Custom's website and saw that they had an upper so I called and they guy said, "let me check to see if we still have any" and he put me on hold and never came back. I waited for 20 minutes on hold and then hung up. I finally called Cajun Gun Works and spoke with David who said that they had two 75B slides left and that he would sell me one. I bought a set of night sights that they sell to go with it and they mounted the nights sights on the slide for me before they shipped it. He said I was lucky to get that one because they are hard to come by.
I don't know why the actual importer is so uptight about selling replacements. Good luck in your search. Those are the only three places I can think of that might have one.