GS is really slow at this. Pdfunite from Poppler is faster.

    wget http://www.cl.cam.ac.uk/~rja14/Papers/book2coverlarge.jpg
    convert book2coverlarge.jpg cover.pdf
    pdfunite cover.pdf *toc.pdf *pref.pdf *acks.pdf SEv2-c*.pdf *biblio.pdf *index.pdf SEv2.pdf