Wouldn't it be as good to simply do a normal remaster with the needed mix of applications? Because of Knoppix's hardware autodetection, I don't see any real benefit to doing it as an exercise in imaging, unless there's something that is difficult to set up in Knoppix.

Or if the default Knoppix set of apps works for you, you could even use a USB drive (since you don't want to use a floppy) to write custom settings for the Knoppix user and they would be written to the default user on install.