I’m surprised none of the 9front guys have explored big endian mode on raspberry pi. They don’t seem like they’d be turned off by the perversity of it.
There is a SPARC compiler and linker but no kernel. So far no one has had the interest to get some old SPARC hardware and do the hacking. There is a SPARC instruction emulator on the system that I used to test some libc modifications recently.
But they must do something with SPARC, right?