racketboy has posted a tutorial that shows you how to cram more than one Dreamcast game onto a CD:
I’ve been cleaning up the files on my PC, including a number of useful text files. Among these files is a tutorial that I picked up a while back that let people put multiple Dreamcast games on a single CD-R. This can be pretty helpful if you want to put a few of your favorite games on one disc to reduce disc swapping. Of course, to be fully legal, you should own the original copies of the games in question, but this makes a handy backup solution.
I haven’t tried this myself, but it looks very useful for preserving your collection of games. Link