I never really worked with MARC much (except for a script for generating patron records once a quarter to load new students and staff into III and somehow we ma

I never really worked with MARC much (except for a script for generating patron records once a quarter to load new students and staff into III and somehow we marked obsolete users to change their status) but I used to work at the successor organization to the University of California Division of Library Automation (nee University Library Automation Program), and one of the folks telling MARC war stories was describing doing this with with a tool he created specifically for creating pathological MARC records. They aggregated records from local systems into the systemwide "Melvyl" (during ULAP they produced microfiche binders of the union catalog) -- I don't know that they ever redistributed the MARC to other display systems.