Someone (it's terrible that I can't remember his name offhand---"that
Polish guy"...I'll remember his name after I send this, no doubt;
(^&) posted some scripts a year or so ago that used fifos, I believe,
and worked with dump (or tar, or maybe whichever?) to create
multi-volume CD-R backups.  It did not use mkisofs, but did use
cdrecord.  Probably with a little work, you could even have it
print labels for your disks.  (^&  And a trivial change should let
it work on DVDs, though I think that the script ran "blind" so
you'd have to tell it the size of the media.

(Most of my data is essentially cached on disk; what I can't easily
restore already is small enough that I just back it up over my LAN
to other disks in other computers.  So I never tried his scripts.
However, a few people commented favorably, and he posted a modified
version that he said he'd been testing successfully.)


If you can't dig it up in the archives, and want it, I can try to
dig it up.  (Assuming that the author doesn't just post a reference.
Hm.  Maybe it should be put into pkgsrc?  Maybe it's already there.
(^&)


Good luck.

-- 
  "I probably don't know what I'm talking about."  http://www.olib.org/~rkr/