iSONEWS
After recently playing around with GC discs I have found out that the GC discs are protected by a barcode on the disc. There are 2, one is small an the other long and thin. The small one does nothing if cover/removed. But if you alter the long one the GC will not boot the disc. Therefore it must mean the GC reads this barcode to validate a real disc. It looks like the Internal workings are based on an APROM boot chip linked to the controller. If the code from this can be hacked then a disc without the barcode can be loaded.
I have heard from a reliable sources that GC discs can be extracted with certain software/hardware...so it is only a matter of time till we will have a GC that will play backups.