As the supply of 50 pin SCSI HDDs dwindles, there has been a fair amount of focus on bridges to attach various more modern storage devices to the SCSI bus. Has anyone seriously looked into bypassing SCSI entirely and interfacing directly to the PDS or NuBus? There has been success in modifying the ROM to implement a ROM disk which I've now got running in an SE/30. This is somewhat limited though as the ROM slot can not address more than 8MB and there is no provision for write enable, but it solves the boot issue and means that the primary storage does not necessarily have to be bootable.

Could the IDE interface used in some of the later 68k Macs be duplicated on an expansion board? Perhaps a simple SD card interface? Other options?