you don't need to create new rom without scsi.device.
Luciferin includes a module to make it skip the ide checks. That has the advantage of you being able to disable it pressing the right (or was it left?) mouse button.
As AmigaOS, MorphOS will work directly without loading any driver. Cybppc.device is in the flashrom.
There are uwscsi round cables. Use 68pin cables and active terminators. For CDs you'll need a 68<--->50 adaptor.
Get IDE<--->UWSCSI (68pin) adaptors. It will be very useful to use cheap IDE hard drives. Get a 300GB one for example. If you don't have an scsi CD it will be easier to buy another ide<--->uwscsi adaptor and use a DVD burner with frying pan than finding an old scsi cdrw and expect it to work flawlessly :-)