[Quall999]

I haven't tried the panasonic.

As for the mini discs, you mean mini DVD's right? Mini DVD's should have a big enouph storage compacity. Mini cd's only have like 125mb which isn't even enouph for any Dreamcast game. GC discs will need at least 650, and thats if you scrap stuff like movies and sound files.
As for that reading cd-rw and all dvd's on xbox, the only reason why this works was because xbox was made to read cd-rw's and not cd-r's. No doubt the panasonic Gamecube reads all cd's and dvd's.

And copying games with CloneCD is never going to work (unless the new version includes a GC DVD protection hack). GC disc are double layered (i think) AND encrypted, much like the xbox. This makes it hard for any DVD-rom to read. Thats why, on the xbox, you have to copy xbox games from the xbox dvd-rom.
Just wait, someone is bound to make a program and a connection to read directly off the Gamecube.