Other idea... I know it this will sound "crazy" but is there any way that Amiga could detect CD-ROM without any other external drivers (considering there is a HDD/CD-ROM on one tape, 4xeide or other solution). I assume there would not be space in ROMs do to it.
The devil is in the detail. Yes, the built-in scsi.device (which speaks IDE, not SCSI) does now support ATAPI, and hence can load from CDROM. Yes, the Os-supplied CDFS is ROM-able and could therefore run from ROM if needed. I have not checked ROM space, but you should also understand that many CDROMs are actually connected to custom host-adapters, and *they* would require a modification to boot from CD as well.
So there is a link missing between the host adapter on one side, and the CDFS on the other side. For traditional file systems, this gap is filled by the RDB, which sits on the harddisk and which is required to be loaded by host adapters, then mounts the file systems and carries the boot process over.
But a standard ISO CD does not have an RDB on it that would mount a device, and could continue booting, and the standard host adapter neither looks for RDBs on optical devices. ISO images either depend on a (PC-based) boot floppy emulation, or the (PC-based) El-Torito boot mechanism, and there is no support for something like this in Amiga-land, leave alone any standard that comes close to it.
Hence, adding the CDFS to ROM does not solve the problem. It would require a modification of host adapter firmware. Given that most (if not all) vendors that made such adapters are out of business, chances are pretty slim that this would ever happen.