I want to do the same thing as you - archive full (or partial) backups on multiple optical discs. It looks as though DropDMG
http://c-command.com/dropdmg/ would fit the bill pretty well. I haven't tried it myself yet, though I intend to.
Alternatively if you're happy writing a shellscript it looks like you can access much of the same functionality using hdiutil:
http://developer.apple.com/documenta...hdiutil.1.html
Since you have SuperDuper you would probably still want to use that to create your backup as a disk image, then use DropDMG or hdiutil to segment and burn it.