A friend at an establshed independent textbook publisher has asked me to help him in his search for a freelance permissions editor. If this is you (or you know someone who does this), please e-mail me at firstname.lastname@example.org and I will put you in touch with one another.
And for the career explorers out there, a permissions editor is someone who identifies material (photos, text, etc.) in a pre-published book that is copyrighted by someone else. The permissions editor then requests permission of the copyrightholders, negotiates the fees, and coordinates the process of getting everything "cleared" legally for publication.
If we manage to turn up someone who does this, I'll ask them to share their career story here.