i'm sorry to hear it, chips i agree that it's insulting for longtime employees of any kind to be treated as if they aren't part of the team. i have no idea how it works in your field, but when people are "excluded" like that from official records, there are usually monetary/budgetary reasons for doing so. that is, the institution/organization/business is saving money somehow by labeling you differently from "regular" employees.

it sounds like you should be continuously applying for any full-time librarian position you can find, making sure to highlight your extensive experience working at many different libraries. but if things in your area aren't working out, maybe you could consider getting away, and moving elsewhere? there's got to be a library out there that wants an experienced librarian like yourself