We'll never see a 680x0 port. It began as a PPC OS anyhow, but yes it was being considered as the future of Amiga around the same time that QNX was and MorphOS was born.
Haiku started life as an x86 only OS, since then it's been partially ported to ARM, PPC and 68k.
edit:
BeOS started life on Hobbit processors not PPC btw.