patch small leaks in ceramic sewage line running through basement
Do you have enough access to the pipe to wrap something completely around it? I know we're not supposed to get carried away with brand names here, but have you searched for anything along the lines of "perma-wrap" or "water activated fiberglass pipe repair wrap?"

Or, cut a curved section of clay or PVC pipe of the right size, clean the pipe and put the cut section over it, then seal it with an industrial sealant that adheres to both materials. Even after that, I would personally wrap the pipe with something like fiberglass. But one of these approaches might create a solid seal and get you by until you can replace the pipe.