Merging distribution CDs

["Moore, Paul" <Paul.Moore@uk.origin-it.com>]

I have a set of four potato unofficial CDs, and a massive hard disk, and I'm
bored of swapping CDs. What is the best way of copying the full contents of
the CDs onto my hard disk so that I can install off there?

I assume that

    mkdir -p /dist/cd[1-4]
    mount /cdrom
    (cd /cdrom && tar cf - .) | (cd /dist/cd1 && tar xf -)
    # repeat 3 more times

works, with appropriate sources.list lines, but can I merge the CDs, to make
a single directory tree - ideally in such a way that I could use this as a
base for a mirror of the FTP site and then update regularly...

Thanks for any suggestions,
Paul.