If you can't find either a Viper520CD or 530, the ultimate all in one case A500 would be an ICD AdIDE in the 68000 cpu slot, internal 2.5" harddisk, 4.5mb fast ram on trapdoor ICD AdRAM card. I wonder if anyone has gotten an ide laptop cdrom to work with the AdIDE board?
Another possibility, though external, is Jens' new Buddha adaptor for the A500 86-pin expansion slot.