To my understanding, the most feasible solution for running the old hardware-banging SW, would be to emulate it on software mode. If the A/box of Morphos was advanced to the state of emulating AGA & ECS, Paula, timers, I/O, and recognising optimal CPU mode for a given application (that is almost impossible), I'm sure noone would miss the old chipset.
now imagine this version of MOS, running on a Pegasos III with the following specs:
Dual-core next gen G4 1.5 GHz with the northbridge integrated in it (DDR2 mem controller, dual PCI-Express bus), a neat southbridge having USB 2.0, firewire, SATA, decent 5.1 sound and 3 "ancient" PCI slots!
MOS would be tailored to take advantage of the 2 CPU cores and developer libraries would provide for target CPU of the 2. That would be one killer of a machine, wouldn't it!
I have the suspicion that I've gone slightly out of subject but anyway...
Custom chips is a thing of the past.