I've been playing around with this tool to manipulate PDF files for my Kobo Touch e-reader: http://www.willus.com/k2pdfopt/ AFAIK, it's the only one that can do several operations (crop, reflow, whatever...) in one go. Pretty interesting! It can use either MuPDF (default) or Ghostscript for rendering. Arch Linux has already a build: we wouldn't like to lag behind right? ;-)